Search space design with overbooking in carrier aggregation

ABSTRACT

Methods, systems, and devices for wireless communications are described that provide for allocation of control channel candidates for multiple component carriers (CCs) in carrier aggregation (CA) communications. A CA limit may correspond to a total number of configurable control channel candidates across multiple CCs. The control channel candidates may include blind decoding (BD) candidates or control channel element (CCE) candidates for channel estimation. A per-CC limit of control channel candidates may correspond to a number of configurable control channel candidates for each CC. An applied set of control channel candidates may be determined by allocating control channel candidates across the multiple CCs based on the CA limit and the per-CC limit. Such techniques may be used in cases where the CCs have a same numerology or mixed numerology, and may also be used for cross-carrier scheduling.

CROSS REFERENCES

The present Application for Patent claims the benefit of U.S.Provisional Application No. 62/670,661 by Xu et al., entitled “SearchSpace Design with Overbooking In Carrier Aggregation,” filed May 11,2018, assigned to the assignee hereof, and expressly incorporated byreference herein in its entirety.

BACKGROUND

The following relates generally to wireless communications, and morespecifically to search space design with overbooking in carrieraggregation.

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., time, frequency, and power). Examples of suchmultiple-access systems include fourth generation (4G) systems such asLong Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, orLTE-A Pro systems, and fifth generation (5G) systems which may bereferred to as New Radio (NR) systems. These systems may employtechnologies such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal frequency division multiple access (OFDMA), or discreteFourier transform-spread-OFDM (DFT-S-OFDM). A wireless multiple-accesscommunications system may include a number of base stations or networkaccess nodes, each simultaneously supporting communication for multiplecommunication devices, which may be otherwise known as user equipment(UE).

In some wireless communications systems, such as those having multiplepossible control channel configurations and/or multiple possibleoverlapping monitoring occasions, search space configurations may allowoverbooking of decoding candidates. For example, overbooking may referto configuring more blind decoding candidates than a UE may be capableof processing. Additionally or alternatively, overbooking may refer tosearch spaces that span an amount of resources that exceeds a UEcapability for performing channel estimation. Further, some wirelesscommunications systems may use carrier aggregation techniques in whichmultiple different component carriers (CCs) may be used for wirelesstransmissions, and overbooking of search spaces across multiple CCs mayoccur. Overbooking of search spaces may present challenges in schedulingand monitoring for downlink control information.

SUMMARY

The described techniques relate to improved methods, systems, devices,or apparatuses that support search space design with overbooking incarrier aggregation. In some cases, due to blind decoding (BD) andcontrol channel element (CCE) channel estimation (CE) limitations, somecontrol channel candidates (e.g., Physical Downlink Control Channel(PDCCH) candidates) of one or more search space sets may need to bedropped (or pruned) for blind decoding and/or CE purposes. Variousaspects of the present disclosure provide for allocation of controlchannel candidates for multiple component carriers (CCs) in carrieraggregation (CA) communications. In some cases, a CA limit maycorrespond to a total number of configurable control channel candidatesacross multiple CCs. The control channel candidates may include blinddecoding (BD) candidates or control channel element (CCE) candidates forchannel estimation. A per-CC limit of control channel candidates maycorrespond to a number of configurable control channel candidates foreach CC. An applied set of control channel candidates may be determinedby allocating control channel candidates across the multiple CCs basedon the CA limit and the per-CC limit. Such techniques may be used incases where the CCs have a same numerology or mixed numerology, and mayalso be used for cross-carrier scheduling.

A method of wireless communication is described. The method may includeestablishing a wireless connection via a set of CCs using CA,determining a CA limit corresponding to a total number of configurablecontrol channel candidates across the set of CCs, the control channelcandidates including BD candidates or CCE candidates for channelestimation, determining a per-CC limit corresponding to a per-CC numberof control channel candidates that are configurable for each CC of theset of CCs, determining an applied set of control channel candidates byallocating control channel candidates across a number of configuredcontrol channel candidates of the set of CCs based on the CA limit andthe per-CC limit, where the number of configured control channelcandidates for at least one CC of the set of CCs may exceed the per-CClimit, and communicating based on the applied set of control channelcandidates.

An apparatus for wireless communication is described. The apparatus mayinclude a processor, memory in electronic communication with theprocessor, and instructions stored in the memory. The instructions maybe executable by the processor to cause the apparatus to establish awireless connection via a set of CCs using CA, determine a CA limitcorresponding to a total number of configurable control channelcandidates across the set of CCs, the control channel candidatesincluding BD candidates or CCE candidates for channel estimation,determine a per-CC limit corresponding to a per-CC number of controlchannel candidates that are configurable for each CC of the set of CCs,determine an applied set of control channel candidates by allocatingcontrol channel candidates across a number of configured control channelcandidates of the set of CCs based on the CA limit and the per-CC limit,where the number of configured control channel candidates for at leastone of the CCs may exceed the per-CC limit, and communicate based on theapplied set of control channel candidates.

Another apparatus for wireless communication is described. The apparatusmay include means for establishing a wireless connection via a set ofCCs using CA, determining a CA limit corresponding to a total number ofconfigurable control channel candidates across the set of CCs, thecontrol channel candidates including BD candidates or CCE candidates forchannel estimation, determining a per-CC limit corresponding to a per-CCnumber of control channel candidates that are configurable for each CCof the set of CCs, determining an applied set of control channelcandidates by allocating control channel candidates across a number ofconfigured control channel candidates of the set of CCs based on the CAlimit and the per-CC limit, where the number of configured controlchannel candidates for at least one of the CCs may exceed the per-CClimit, and communicating based on the applied set of control channelcandidates.

A non-transitory computer-readable medium storing code for wirelesscommunication is described. The code may include instructions executableby a processor to establish a wireless connection via a set of CCs usingCA, determine a CA limit corresponding to a total number of configurablecontrol channel candidates across the set of CCs, the control channelcandidates including BD candidates or CCE candidates for channelestimation, determine a per-CC limit corresponding to a per-CC number ofcontrol channel candidates that are configurable for each CC of the setof CCs, determine an applied set of control channel candidates byallocating control channel candidates across a number of configuredcontrol channel candidates of the set of CCs based on the CA limit andthe per-CC limit, where the number of configured control channelcandidates for at least one of the CCs may exceed the per-CC limit, andcommunicate based on the applied set of control channel candidates.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the determining the appliedset of control channel candidates may include operations, features,means, or instructions for allocating control channel candidatesseparately for each CC of the set of CCs, the control channel candidatesfor each CC allocated to comply with the per-CC limit. In some examplesof the method, apparatuses, and non-transitory computer-readable mediumdescribed herein, a UE may be capable of supporting a first number ofCCs, and where a second number of CCs in the set of CCs may be less thanor equal to the first number of CCs, and where the control channelcandidates for each CC may be separately allocated to each comply withthe per-CC limit.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, a UE may be capable ofsupporting a first number of CCs, and where a second number of CCs inthe set of CCs may be greater than the first number of CCs. In someexamples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the determining the appliedset of control channel candidates may include operations, features,means, or instructions for selecting a subset of CCs from the set ofCCs, the subset of CCs having a third number of CCs corresponding to thefirst number of CCs and allocating control channel candidates across thesubset of CCs, where the control channel candidates for each CC of thesubset of CCs may be separately allocated to each comply with the per-CClimit.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the per-CC limit for each CCof the set of CCs may be defined by a set of non-negative numbers suchthat the per-CC limit may be a product of a selected non-negativenumber, the first number of CCs, and a single carrier limit of controlchannel candidates that may be configurable for a single non-CA carrier,and where the selected non-negative number may be based on whether a BDlimit budget or a CCE limit budget may be distributed evenly,proportional to a bandwidth, or proportional to configured controlchannel candidates, for each CC. In some examples of the method,apparatuses, and non-transitory computer-readable medium describedherein, a sum of the set of non-negative numbers selected for each CC ofthe set of CCs equals one. In some examples of the method, apparatuses,and non-transitory computer-readable medium described herein, eachnon-negative number may be less than or equal to one divided by thefirst number of CCs.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the determining the appliedset of control channel candidates may include operations, features,means, or instructions for distributing a BD limit budget or a CCE limitbudget evenly across the second number of CCs, where a portion of the BDlimit budget or the CCE limit budget for each CC corresponds to aproduct of the first number of CCs and the per-CC limit divided by thesecond number of CCs. In some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein, thedetermining the applied set of control channel candidates may includeoperations, features, means, or instructions for distributing a BD limitbudget or a CCE limit budget across the second number of CCs accordingto a bandwidth-proportional distribution, where a portion of the BDlimit budget or the CCE limit budget for each CC corresponds to aproduct of the first number of CCs, the per-CC limit, and a bandwidth ofthe associated CC, divided by a total cumulative bandwidth of the secondnumber of CCs. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein the bandwidthof the associated CC corresponds to a bandwidth of a number of controlresource sets (CORESETs), an active bandwidth part (BWP), or a cellbandwidth of the associated CC.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the determining the appliedset of control channel candidates may include operations, features,means, or instructions for distributing a BD limit budget or a CCE limitbudget across the second number of CCs according to a slot-basedproportional distribution, where a portion of the BD limit budget or theCCE limit budget for each CC corresponds to a product of the firstnumber of CCs, the per-CC limit, and a number of BDs or CCEs associatedwith the configured control channel candidates of the associated CC foran associated slot, divided by a total cumulative number of configuredcontrol channel candidates of the second number of CCs.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the determining the appliedset of control channel candidates may include operations, features,means, or instructions for reducing a number of CCs of the set of CCsthat can be scheduled with control channel transmissions to correspondto the second number of CCs, and distributing a BD limit budget or a CCElimit budget across configured control channel candidates of the reducednumber of CCs; or and maintaining the per-CC limit for a first subset ofCCs and distributing remaining of the CA limit control channelcandidates among remaining CCs of the set of CCs.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the determining the appliedset of control channel candidates may include operations, features,means, or instructions for identifying a set of search space (SS) setsthat indicate, for each CC of the set of CCs, associated resources foravailable control channel candidates and mapping the set of SS sets ofeach CC of the set of CCs up to the per-CC limit to determine theapplied set of control channel candidates for the corresponding CC,where each CC of the set of CCs may have an ordered CC index, and wherethe mapping may be from a lowest CC index to a highest CC index.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the determining the appliedset of control channel candidates may include operations, features,means, or instructions for identifying a set of SS sets that eachindicate associated resources for available control channel candidatesfor two or more CCs, where each CC set may have a SS set index andmapping the each CC associated with each SS set to determine the appliedset of control channel candidates for the corresponding SS set, where acontrol channel candidate for a CC may be skipped if the per-CC limitfor the corresponding CC may be reached or the CC may be fully mapped,and where the mapping may be from a lowest SS index to a highest SSindex.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, a UE may be capable ofsupporting a first number of CCs, and where a second number of CCs inthe set of CCs may be greater than the first number of CCs, and wherethe determining the applied set of control channel candidates mayinclude operations, features, means, or instructions for allocatingcontrol channel candidates jointly for the set of CCs, the controlchannel candidates for each CC allocated to comply with the per-CC limitand the CA limit. In some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein, the allocatingthe control channel candidates may include operations, features, means,or instructions for identifying a set of SS sets that indicate, for eachCC of the set of CCs, associated resources for available control channelcandidates, mapping the set of SS sets of each CC of the set of CCs upto the per-CC limit to determine the applied set of control channelcandidates for the corresponding CC, where each CC of the set of CCs mayhave an ordered CC index, and where the mapping may be from a lowest CCindex to a highest CC index, maintaining a cumulative count of mappedcontrol channel candidates across the set of CCs and stopping themapping if the cumulative count reaches the CA limit. In some examplesof the method, apparatuses, and non-transitory computer-readable mediumdescribed herein, the allocating the control channel candidates mayinclude operations, features, means, or instructions for identifying setof SS sets that each indicate associated resources for available controlchannel candidates for two or more CCs, where each CC set may have a SSset index, mapping the each CC associated with each SS set to determinethe applied set of control channel candidates for the corresponding SSset, where a control channel candidate for a CC may be skipped if theper-CC limit for the corresponding CC may be reached or the CC may befully mapped, and where the mapping may be from a lowest SS index to ahighest SS index, maintaining a cumulative count of mapped controlchannel candidates across the set of SS sets and stopping the mapping ifthe cumulative count reaches the CA limit. In some examples of themethod, apparatuses, and non-transitory computer-readable mediumdescribed herein, a number of CCs of the set of CCs that can bescheduled with control channel candidates may be unknown until theallocating may be finished.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the set of CCs includes atleast a first CC having a first SCS and a second CC having a second SCSthat may be different than the first SCS. In some examples of themethod, apparatuses, and non-transitory computer-readable mediumdescribed herein, the first CC may be a scheduling CC that providesscheduling information for each of the CCs of the set of CCs, and wherethe first SCS may be used in determining the CA limit for the schedulingCC and each of the CCs of the set of CCs that is provided schedulinginformation. In some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein, the first CCmay be a scheduling CC that provides scheduling information for thesecond CC, and where the first SCS may be used for the second CC fordetermining the applied set of control channel candidates.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the determining the appliedset of control channel candidates may include operations, features,means, or instructions for allocating a BD limit budget or a CCE limitbudget separately for each CC of the set of CCs based on control channelcandidates for each CC that may be allocated to comply with the per-CClimit.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, a UE may be capable ofsupporting a first number of CCs, and where a second number of CCs inthe set of CCs may be greater than the first number of CCs, and wherethe determining the applied set of control channel candidates mayinclude operations, features, means, or instructions for identifying thefirst SCS as a reference SCS and identifying a reference slot durationbased on the reference SCS, determining a second slot duration of thesecond CC based on the second SCS, determining the per-CC limit of thesecond CC based on the second slot duration relative to the referenceslot duration and allocating control channel candidates jointly for theset of CCs, the control channel candidates for each CC allocated tocomply with the per-CC limit and the CA limit.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the allocating the controlchannel candidates may include operations, features, means, orinstructions for counting a number of control channel candidates foreach reference slot duration for each CC, calculating a total number ofcontrol channel candidates for each CC in the reference slot durationand allocating a set of BDs or CCEs to a total number control channelcandidates for each CC to comply with the per-CC limit and the CA limit.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the allocating the controlchannel candidates further may include operations, features, means, orinstructions for identifying a set of SS sets that indicate, for each CCof the set of CCs, associated resources for available control channelcandidates, mapping the set of SS sets of each CC of the set of CCs upto the per-CC limit to determine the applied set of control channelcandidates for the corresponding CC, where each CC of the set of CCs mayhave an ordered CC index, and where the mapping may be from a lowest CCindex to a highest CC index, maintaining a cumulative count of mappedcontrol channel candidates across the set of CCs and stopping themapping if the cumulative count reaches the CA limit.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the allocating the controlchannel candidates further may include operations, features, means, orinstructions for identifying set of SS sets that each indicateassociated resources for available control channel candidates for two ormore CCs, where each CC set may have a SS set index, mapping the each CCassociated with each SS set to determine the applied set of controlchannel candidates for the corresponding SS set, where a control channelcandidate for a CC may be skipped if the per-CC limit for thecorresponding CC may be reached or the CC may be fully mapped, and wherethe mapping may be from a lowest SS index to a highest SS index,maintaining a cumulative count of mapped control channel candidatesacross the set of SS sets and stopping the mapping if the cumulativecount reaches the CA limit. In some examples of the method, apparatuses,and non-transitory computer-readable medium described herein, a smallestSCS of the first SCS and the second SCS may be selected as the referenceSCS.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the first SCS may be smallerthan the second SCS, the second SCS may be the reference SCS, and firstslot duration of the first CC may be longer than the reference slotduration, and where the total number of control channel candidates foreach CC in the reference slot duration may be adjusted based a portionof the first slot duration that overlaps with a subsequent referenceslot duration.

A method of wireless communication is described. The method may includeestablishing a wireless connection via two or more CCs using CA,identifying a first subset of the two or more CCs in which configuredcontrol channel candidates may exceed a per-CC limit of control channelcandidates for each CC, the control channel candidates corresponding tolocations for control channel processing objects for BD or CCEs forchannel estimation, identifying a second subset of the two or more CCsin which the number of configured control channel candidates comply withthe per-CC limit of control channel candidates for each CC, determiningan applied set of control channel candidates for the first subset of twoor more CCs by mapping control channel candidates across the firstsubset of two or more CCs such that mapped control channel candidatescomply with the per-CC limit, and communicating based on the applied setof control channel candidates.

An apparatus for wireless communication is described. The apparatus mayinclude a processor, memory in electronic communication with theprocessor, and instructions stored in the memory. The instructions maybe executable by the processor to cause the apparatus to establish awireless connection via two or more CCs using CA, identify a firstsubset of the two or more CCs in which configured control channelcandidates may exceed a per-CC limit of control channel candidates foreach CC, the control channel candidates corresponding to locations forcontrol channel processing objects for BD or CCEs for channelestimation, identify a second subset of the two or more CCs in which thenumber of configured control channel candidates comply with the per-CClimit of control channel candidates for each CC, determine an appliedset of control channel candidates for the first subset of CCs by mappingcontrol channel candidates across the first subset of CCs such thatmapped control channel candidates comply with the per-CC limit, andcommunicate based on the applied set of control channel candidates.

Another apparatus for wireless communication is described. The apparatusmay include means for establishing a wireless connection via two or moreCCs using CA, identifying a first subset of the two or more CCs in whichconfigured control channel candidates may exceed a per-CC limit ofcontrol channel candidates for each CC, the control channel candidatescorresponding to locations for control channel processing objects for BDor CCEs for channel estimation, identifying a second subset of the twoor more CCs in which the number of configured control channel candidatescomply with the per-CC limit of control channel candidates for each CC,determining an applied set of control channel candidates for the firstsubset of CCs by mapping control channel candidates across the firstsubset of CCs such that mapped control channel candidates comply withthe per-CC limit, and communicating based on the applied set of controlchannel candidates.

A non-transitory computer-readable medium storing code for wirelesscommunication is described. The code may include instructions executableby a processor to establish a wireless connection via two or more CCsusing CA, identify a first subset of the two or more CCs in whichconfigured control channel candidates may exceed a per-CC limit ofcontrol channel candidates for each CC, the control channel candidatescorresponding to locations for control channel processing objects for BDor CCEs for channel estimation, identify a second subset of the two ormore CCs in which the number of configured control channel candidatescomply with the per-CC limit of control channel candidates for each CC,determine an applied set of control channel candidates for the firstsubset of CCs by mapping control channel candidates across the firstsubset of CCs such that mapped control channel candidates comply withthe per-CC limit, and communicate based on the applied set of controlchannel candidates.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the number of configuredcontrol channel candidates complies with a per-CA limit of controlchannel candidates for the two or more CCs.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the first subset of the twoor more CCs includes a primary component carrier (PCC), a primarysecondary component carrier (PSCC) and the second subset of the two ormore CCs includes one or more secondary component carriers (SCCs). Insome examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the two or more CCs includesat least a first CC having a first sub-carrier spacing (SCS), and aprimary secondary component carrier (PSCC) and a second CC having asecond SCS that may be different than the first SCS.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system for wireless communications inaccordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a portion of a wireless communicationssystem in accordance with aspects of the present disclosure.

FIG. 3 illustrates an example of a BD/CCE mapping in accordance withaspects of the present disclosure.

FIG. 4 illustrates an example of a mixed numerology CC configuration inaccordance with aspects of the present disclosure.

FIG. 5 illustrates an example of cross-carrier scheduling in accordancewith aspects of the present disclosure.

FIG. 6 illustrates an example of a mixed numerology reference slot inaccordance with aspects of the present disclosure.

FIG. 7 illustrates another example of a mixed numerology reference slotin accordance with aspects of the present disclosure.

FIGS. 8 and 9 show block diagrams of devices in accordance with aspectsof the present disclosure.

FIG. 10 shows a block diagram of a communications manager in accordancewith aspects of the present disclosure.

FIG. 11 shows a diagram of a system including a user equipment (UE) inaccordance with aspects of the present disclosure.

FIG. 12 shows a diagram of a system including a base station inaccordance with aspects of the present disclosure.

FIGS. 13 and 14 show flowcharts illustrating methods in accordance withaspects of the present disclosure.

DETAILED DESCRIPTION

Various described techniques provide search space design withoverbooking in carrier aggregation (CA), in which control channelcandidates may be allocated across component carriers (CCs) such that aper-CC limit and CA limit on the number of blind decodes or channelestimations to be performed by a user equipment (UE) are within the UEcapability. Such techniques may be used in wireless communicationssystems in which a base station may transmit downlink controlinformation (DCI) to a UE or a group of UEs. The UEs may use the DCI tosupport communications with the base station. The base station mayconfigure search space sets according to control channel candidates(e.g., Physical Downlink Control Channel (PDCCH) candidates) at one ormore aggregation levels to use for these DCI transmissions. Whenconfiguring a search space set, the base station may determine a controlresource set (CORESET) containing the search space set. This CORESET mayinclude a number of control channel elements (CCEs) and the search spaceset may be mapped to a CCE space corresponding to a subset of CCEs ofthe CORESET. The UEs may identify this search space set configuration,and may monitor the CCEs corresponding to the control channel candidatesfor any DCI transmissions from the base station. A control region may bea search space monitoring occasion for one or more search space setsthat has a common reference signal configuration (e.g., shares ascrambling sequence, etc.).

As indicated above, in some cases, due to blind decoding (BD) and CCEchannel estimation limitations, some control channel candidates (e.g.,PDCCH candidates) of one or more search space sets may need to bedropped (or pruned) for blind decoding and/or CE purposes. Variousaspects of the present disclosure provide for allocation of controlchannel candidates for multiple component carriers (CCs) in carrieraggregation (CA) communications. In some cases, a CA limit maycorrespond to a total number of configurable control channel candidatesacross multiple CCs. The control channel candidates may include blinddecoding (BD) candidates or control channel element (CCE) candidates forchannel estimation. A per-CC limit of control channel candidates maycorrespond to a number of configurable control channel candidates foreach CC. An applied set of control channel candidates may be determinedby allocating control channel candidates across the multiple CCs basedon the CA limit and the per-CC limit. Such techniques may be used incases where the CCs have a same numerology or mixed numerology, and mayalso be used for cross-carrier scheduling.

In some cases, the per-CC limit may be applied to each configured CC. Incases where a UE is capable of supporting all of the configured CCs,complying with the per-CC limit will also result in compliance with theCA limit, and control channel candidates may be allocated for each CC inaccordance with the per-CC limit. In cases where a user equipment (UE)is capable of supporting fewer CCs than are configured, however, theper-CC limit may result in more control channel candidates that the UEis capable of handling. In such cases, the per-CC limit for one or moreof the CCs may be adjusted such that the CA limit is met.

Aspects of the disclosure are initially described in the context of awireless communications system. Various examples of allocations andmappings across multiple CCs are then discussed. Aspects of thedisclosure are further illustrated by and described with reference toapparatus diagrams, system diagrams, and flowcharts that relate tosearch space design with overbooking in carrier aggregation.

FIG. 1 illustrates an example of a wireless communications system 100that supports search space design with overbooking in carrieraggregation in accordance with aspects of the present disclosure. Thewireless communications system 100 includes base stations 105, UEs 115,and a core network 130. In some examples, the wireless communicationssystem 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced(LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. Insome cases, wireless communications system 100 may support enhancedbroadband communications, ultra-reliable (e.g., mission critical)communications, low latency communications, or communications withlow-cost and low-complexity devices.

Base stations 105 may wirelessly communicate with UEs 115 via one ormore base station antennas. Base stations 105 described herein mayinclude or may be referred to by those skilled in the art as a basetransceiver station, a radio base station, an access point, a radiotransceiver, a NodeB, an eNodeB (eNB), a next-generation Node B orgiga-nodeB (either of which may be referred to as a gNB), a Home NodeB,a Home eNodeB, or some other suitable terminology. Wirelesscommunications system 100 may include base stations 105 of differenttypes (e.g., macro or small cell base stations). The UEs 115 describedherein may be able to communicate with various types of base stations105 and network equipment including macro eNBs, small cell eNBs, gNBs,relay base stations, and the like.

Each base station 105 may be associated with a particular geographiccoverage area 110 in which communications with various UEs 115 issupported. Each base station 105 may provide communication coverage fora respective geographic coverage area 110 via communication links 125,and communication links 125 between a base station 105 and a UE 115 mayutilize one or more carriers. Communication links 125 shown in wirelesscommunications system 100 may include uplink transmissions from a UE 115to a base station 105, or downlink transmissions from a base station 105to a UE 115. Downlink transmissions may also be called forward linktransmissions while uplink transmissions may also be called reverse linktransmissions.

The geographic coverage area 110 for a base station 105 may be dividedinto sectors making up only a portion of the geographic coverage area110, and each sector may be associated with a cell. For example, eachbase station 105 may provide communication coverage for a macro cell, asmall cell, a hot spot, or other types of cells, or various combinationsthereof. In some examples, a base station 105 may be movable andtherefore provide communication coverage for a moving geographiccoverage area 110. In some examples, different geographic coverage areas110 associated with different technologies may overlap, and overlappinggeographic coverage areas 110 associated with different technologies maybe supported by the same base station 105 or by different base stations105. The wireless communications system 100 may include, for example, aheterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different typesof base stations 105 provide coverage for various geographic coverageareas 110.

The term “cell” refers to a logical communication entity used forcommunication with a base station 105 (e.g., over a carrier), and may beassociated with an identifier for distinguishing neighboring cells(e.g., a physical cell identifier (PCID), a virtual cell identifier(VCID)) operating via the same or a different carrier. In some examples,a carrier may support multiple cells, and different cells may beconfigured according to different protocol types (e.g., machine-typecommunication (MTC), narrowband Internet-of-Things (NB-IoT), enhancedmobile broadband (eMBB), or others) that may provide access fordifferent types of devices. In some cases, the term “cell” may refer toa portion of a geographic coverage area 110 (e.g., a sector) over whichthe logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system100, and each UE 115 may be stationary or mobile. A UE 115 may also bereferred to as a mobile device, a wireless device, a remote device, ahandheld device, or a subscriber device, or some other suitableterminology, where the “device” may also be referred to as a unit, astation, a terminal, or a client. A UE 115 may also be a personalelectronic device such as a cellular phone, a personal digital assistant(PDA), a tablet computer, a laptop computer, or a personal computer. Insome examples, a UE 115 may also refer to a wireless local loop (WLL)station, an Internet of Things (IoT) device, an Internet of Everything(IoE) device, or an MTC device, or the like, which may be implemented invarious articles such as appliances, vehicles, meters, or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or lowcomplexity devices, and may provide for automated communication betweenmachines (e.g., via Machine-to-Machine (M2M) communication). M2Mcommunication or MTC may refer to data communication technologies thatallow devices to communicate with one another or a base station 105without human intervention. In some examples, M2M communication or MTCmay include communications from devices that integrate sensors or metersto measure or capture information and relay that information to acentral server or application program that can make use of theinformation or present the information to humans interacting with theprogram or application. Some UEs 115 may be designed to collectinformation or enable automated behavior of machines. Examples ofapplications for MTC devices include smart metering, inventorymonitoring, water level monitoring, equipment monitoring, healthcaremonitoring, wildlife monitoring, weather and geological eventmonitoring, fleet management and tracking, remote security sensing,physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reducepower consumption, such as half-duplex communications (e.g., a mode thatsupports one-way communication via transmission or reception, but nottransmission and reception simultaneously). In some examples half-duplexcommunications may be performed at a reduced peak rate. Other powerconservation techniques for UEs 115 include entering a power saving“deep sleep” mode when not engaging in active communications, oroperating over a limited bandwidth (e.g., according to narrowbandcommunications). In some cases, UEs 115 may be designed to supportcritical functions (e.g., mission critical functions), and a wirelesscommunications system 100 may be configured to provide ultra-reliablecommunications for these functions.

In some cases, a UE 115 may also be able to communicate directly withother UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device(D2D) protocol). One or more of a group of UEs 115 utilizing D2Dcommunications may be within the geographic coverage area 110 of a basestation 105. Other UEs 115 in such a group may be outside the geographiccoverage area 110 of a base station 105, or be otherwise unable toreceive transmissions from a base station 105. In some cases, groups ofUEs 115 communicating via D2D communications may utilize a one-to-many(1:M) system in which each UE 115 transmits to every other UE 115 in thegroup. In some cases, a base station 105 facilitates the scheduling ofresources for D2D communications. In other cases, D2D communications arecarried out between UEs 115 without the involvement of a base station105.

Base stations 105 may communicate with the core network 130 and with oneanother. For example, base stations 105 may interface with the corenetwork 130 through backhaul links 132 (e.g., via an S1, N2, N3, orother interface). Base stations 105 may communicate with one anotherover backhaul links 134 (e.g., via an X2, Xn, or other interface) eitherdirectly (e.g., directly between base stations 105) or indirectly (e.g.,via core network 130).

The core network 130 may provide user authentication, accessauthorization, tracking, Internet Protocol (IP) connectivity, and otheraccess, routing, or mobility functions. The core network 130 may be anevolved packet core (EPC), which may include at least one mobilitymanagement entity (MME), at least one serving gateway (S-GW), and atleast one Packet Data Network (PDN) gateway (P-GW). The MME may managenon-access stratum (e.g., control plane) functions such as mobility,authentication, and bearer management for UEs 115 served by basestations 105 associated with the EPC. User IP packets may be transferredthrough the S-GW, which itself may be connected to the P-GW. The P-GWmay provide IP address allocation as well as other functions. The P-GWmay be connected to the network operators IP services. The operators IPservices may include access to the Internet, Intranet(s), an IPMultimedia Subsystem (IMS), or a Packet-Switched (PS) Streaming Service.

At least some of the network devices, such as a base station 105, mayinclude subcomponents such as an access network entity, which may be anexample of an access node controller (ANC). Each access network entitymay communicate with UEs 115 through a number of other access networktransmission entities, which may be referred to as a radio head, a smartradio head, or a transmission/reception point (TRP). In someconfigurations, various functions of each access network entity or basestation 105 may be distributed across various network devices (e.g.,radio heads and access network controllers) or consolidated into asingle network device (e.g., a base station 105).

Wireless communications system 100 may operate using one or morefrequency bands, typically in the range of 300 MHz to 300 GHz.Generally, the region from 300 MHz to 3 GHz is known as the ultra-highfrequency (UHF) region or decimeter band, since the wavelengths rangefrom approximately one decimeter to one meter in length. UHF waves maybe blocked or redirected by buildings and environmental features.However, the waves may penetrate structures sufficiently for a macrocell to provide service to UEs 115 located indoors. Transmission of UHFwaves may be associated with smaller antennas and shorter range (e.g.,less than 100 km) compared to transmission using the smaller frequenciesand longer waves of the high frequency (HF) or very high frequency (VHF)portion of the spectrum below 300 MHz.

Wireless communications system 100 may also operate in a super highfrequency (SHF) region using frequency bands from 3 GHz to 30 GHz, alsoknown as the centimeter band. The SHF region includes bands such as the5 GHz industrial, scientific, and medical (ISM) bands, which may be usedopportunistically by devices that can tolerate interference from otherusers.

Wireless communications system 100 may also operate in an extremely highfrequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz),also known as the millimeter band. In some examples, wirelesscommunications system 100 may support millimeter wave (mmW)communications between UEs 115 and base stations 105, and EHF antennasof the respective devices may be even smaller and more closely spacedthan UHF antennas. In some cases, this may facilitate use of antennaarrays within a UE 115. However, the propagation of EHF transmissionsmay be subject to even greater atmospheric attenuation and shorter rangethan SHF or UHF transmissions. Techniques disclosed herein may beemployed across transmissions that use one or more different frequencyregions, and designated use of bands across these frequency regions maydiffer by country or regulating body.

In some cases, wireless communications system 100 may utilize bothlicensed and unlicensed radio frequency spectrum bands. For example,wireless communications system 100 may employ License Assisted Access(LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technologyin an unlicensed band such as the 5 GHz ISM band. When operating inunlicensed radio frequency spectrum bands, wireless devices such as basestations 105 and UEs 115 may employ listen-before-talk (LBT) proceduresto ensure a frequency channel is clear before transmitting data. In somecases, operations in unlicensed bands may be based on a CA configurationin conjunction with CCs operating in a licensed band (e.g., LAA).Operations in unlicensed spectrum may include downlink transmissions,uplink transmissions, peer-to-peer transmissions, or a combination ofthese. Duplexing in unlicensed spectrum may be based on frequencydivision duplexing (FDD), time division duplexing (TDD), or acombination of both.

In some examples, base station 105 or UE 115 may be equipped withmultiple antennas, which may be used to employ techniques such astransmit diversity, receive diversity, multiple-input multiple-output(MIMO) communications, or beamforming. For example, wirelesscommunications system 100 may use a transmission scheme between atransmitting device (e.g., a base station 105) and a receiving device(e.g., a UE 115), where the transmitting device is equipped withmultiple antennas and the receiving devices are equipped with one ormore antennas. MIMO communications may employ multipath signalpropagation to increase the spectral efficiency by transmitting orreceiving multiple signals via different spatial layers, which may bereferred to as spatial multiplexing. The multiple signals may, forexample, be transmitted by the transmitting device via differentantennas or different combinations of antennas. Likewise, the multiplesignals may be received by the receiving device via different antennasor different combinations of antennas. Each of the multiple signals maybe referred to as a separate spatial stream, and may carry bitsassociated with the same data stream (e.g., the same codeword) ordifferent data streams. Different spatial layers may be associated withdifferent antenna ports used for channel measurement and reporting. MIMOtechniques include single-user MIMO (SU-MIMO) where multiple spatiallayers are transmitted to the same receiving device, and multiple-userMIMO (MU-MIMO) where multiple spatial layers are transmitted to multipledevices.

Beamforming, which may also be referred to as spatial filtering,directional transmission, or directional reception, is a signalprocessing technique that may be used at a transmitting device or areceiving device (e.g., a base station 105 or a UE 115) to shape orsteer an antenna beam (e.g., a transmit beam or receive beam) along aspatial path between the transmitting device and the receiving device.Beamforming may be achieved by combining the signals communicated viaantenna elements of an antenna array such that signals propagating atparticular orientations with respect to an antenna array experienceconstructive interference while others experience destructiveinterference. The adjustment of signals communicated via the antennaelements may include a transmitting device or a receiving deviceapplying certain amplitude and phase offsets to signals carried via eachof the antenna elements associated with the device. The adjustmentsassociated with each of the antenna elements may be defined by abeamforming weight set associated with a particular orientation (e.g.,with respect to the antenna array of the transmitting device orreceiving device, or with respect to some other orientation).

In some cases, the antennas of a base station 105 or UE 115 may belocated within one or more antenna arrays, which may support MIMOoperations, or transmit or receive beamforming. For example, one or morebase station antennas or antenna arrays may be co-located at an antennaassembly, such as an antenna tower. In some cases, antennas or antennaarrays associated with a base station 105 may be located in diversegeographic locations. A base station 105 may have an antenna array witha number of rows and columns of antenna ports that the base station 105may use to support beamforming of communications with a UE 115.Likewise, a UE 115 may have one or more antenna arrays that may supportvarious MIMO or beamforming operations.

In some cases, wireless communications system 100 may be a packet-basednetwork that operate according to a layered protocol stack. In the userplane, communications at the bearer or Packet Data Convergence Protocol(PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may insome cases perform packet segmentation and reassembly to communicateover logical channels. A Medium Access Control (MAC) layer may performpriority handling and multiplexing of logical channels into transportchannels. The MAC layer may also use hybrid automatic repeat request(HARQ) to provide retransmission at the MAC layer to improve linkefficiency. In the control plane, the Radio Resource Control (RRC)protocol layer may provide establishment, configuration, and maintenanceof an RRC connection between a UE 115 and a base station 105 or corenetwork 130 supporting radio bearers for user plane data. At thePhysical (PHY) layer, transport channels may be mapped to physicalchannels.

In some cases, UEs 115 and base stations 105 may support retransmissionsof data to increase the likelihood that data is received successfully.HARQ feedback is one technique of increasing the likelihood that data isreceived correctly over a communication link 125. HARQ may include acombination of error detection (e.g., using a cyclic redundancy check(CRC)), forward error correction (FEC), and retransmission (e.g.,automatic repeat request (ARQ)). HARQ may improve throughput at the MAClayer in poor radio conditions (e.g., signal-to-noise conditions). Insome cases, a wireless device may support same-slot HARQ feedback, wherethe device may provide HARQ feedback in a specific slot for datareceived in a previous symbol in the slot. In other cases, the devicemay provide HARQ feedback in a subsequent slot, or according to someother time interval.

Time intervals in LTE or NR may be expressed in multiples of a basictime unit, which may, for example, refer to a sampling period ofT_(s)=1/30,720,000 seconds. Time intervals of a communications resourcemay be organized according to radio frames each having a duration of 10milliseconds (ms), where the frame period may be expressed asT_(f)=307,200 T_(s). The radio frames may be identified by a systemframe number (SFN) ranging from 0 to 1023. Each frame may include 10subframes numbered from 0 to 9, and each subframe may have a duration of1 ms. A subframe may be further divided into 2 slots each having aduration of 0.5 ms, and each slot may contain 6 or 7 modulation symbolperiods (e.g., depending on the length of the cyclic prefix prepended toeach symbol period). Excluding the cyclic prefix, each symbol period maycontain 2048 sampling periods. In some cases, a subframe may be thesmallest scheduling unit of the wireless communications system 100, andmay be referred to as a transmission time interval (TTI). In othercases, a smallest scheduling unit of the wireless communications system100 may be shorter than a subframe or may be dynamically selected (e.g.,in bursts of shortened TTIs (sTTIs) or in selected component carriersusing sTTIs).

In some wireless communications systems, a slot may further be dividedinto multiple mini-slots containing one or more symbols. In someinstances, a symbol of a mini-slot or a mini-slot may be the smallestunit of scheduling. Each symbol may vary in duration depending on thesubcarrier spacing or frequency band of operation, for example. Further,some wireless communications systems may implement slot aggregation inwhich multiple slots or mini-slots are aggregated together and used forcommunication between a UE 115 and a base station 105.

The term “carrier” refers to a set of radio frequency spectrum resourceshaving a defined physical layer structure for supporting communicationsover a communication link 125. For example, a carrier of a communicationlink 125 may include a portion of a radio frequency spectrum band thatis operated according to physical layer channels for a given radioaccess technology. Each physical layer channel may carry user data,control information, or other signaling. A carrier may be associatedwith a pre-defined frequency channel (e.g., an E-UTRA absolute radiofrequency channel number (EARFCN)), and may be positioned according to achannel raster for discovery by UEs 115. Carriers may be downlink oruplink (e.g., in an FDD mode), or be configured to carry downlink anduplink communications (e.g., in a TDD mode). In some examples, signalwaveforms transmitted over a carrier may be made up of multiplesub-carriers (e.g., using multi-carrier modulation (MCM) techniques suchas OFDM or DFT-s-OFDM).

The organizational structure of the carriers may be different fordifferent radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR,etc.). For example, communications over a carrier may be organizedaccording to TTIs or slots, each of which may include user data as wellas control information or signaling to support decoding the user data. Acarrier may also include dedicated acquisition signaling (e.g.,synchronization signals or system information, etc.) and controlsignaling that coordinates operation for the carrier. In some examples(e.g., in a carrier aggregation configuration), a carrier may also haveacquisition signaling or control signaling that coordinates operationsfor other carriers.

Physical channels may be multiplexed on a carrier according to varioustechniques. A physical control channel and a physical data channel maybe multiplexed on a downlink carrier, for example, using time divisionmultiplexing (TDM) techniques, frequency division multiplexing (FDM)techniques, or hybrid TDM-FDM techniques. In some examples, controlinformation transmitted in a physical control channel may be distributedbetween different control regions in a cascaded manner (e.g., between acommon control region or common search space and one or more UE-specificcontrol regions or UE-specific search spaces).

A carrier may be associated with a particular bandwidth of the radiofrequency spectrum, and in some examples the carrier bandwidth may bereferred to as a “system bandwidth” of the carrier or the wirelesscommunications system 100. For example, the carrier bandwidth may be oneof a number of predetermined bandwidths for carriers of a particularradio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz). Insome examples, each served UE 115 may be configured for operating overportions or all of the carrier bandwidth. In other examples, some UEs115 may be configured for operation using a narrowband protocol typethat is associated with a predefined portion or range (e.g., set ofsubcarriers or RBs) within a carrier (e.g., “in-band” deployment of anarrowband protocol type).

In a system employing MCM techniques, a resource element may consist ofone symbol period (e.g., a duration of one modulation symbol) and onesubcarrier, where the symbol period and subcarrier spacing are inverselyrelated. The number of bits carried by each resource element may dependon the modulation scheme (e.g., the order of the modulation scheme).Thus, the more resource elements that a UE 115 receives and the higherthe order of the modulation scheme, the higher the data rate may be forthe UE 115. In MIMO systems, a wireless communications resource mayrefer to a combination of a radio frequency spectrum resource, a timeresource, and a spatial resource (e.g., spatial layers), and the use ofmultiple spatial layers may further increase the data rate forcommunications with a UE 115.

Devices of the wireless communications system 100 (e.g., base stations105 or UEs 115) may have a hardware configuration that supportscommunications over a particular carrier bandwidth, or may beconfigurable to support communications over one of a set of carrierbandwidths. In some examples, the wireless communications system 100 mayinclude base stations 105 and/or UEs 115 that can support simultaneouscommunications via carriers associated with more than one differentcarrier bandwidth.

Wireless communications system 100 may support communication with a UE115 on multiple cells or carriers, a feature which may be referred to ascarrier aggregation (CA) or multi-carrier operation. A UE 115 may beconfigured with multiple downlink CCs and one or more uplink CCsaccording to a carrier aggregation configuration. Carrier aggregationmay be used with both FDD and TDD component carriers.

In some cases, wireless communications system 100 may utilize enhancedcomponent carriers (eCCs). An eCC may be characterized by one or morefeatures including wider carrier or frequency channel bandwidth, shortersymbol duration, shorter TTI duration, or modified control channelconfiguration. In some cases, an eCC may be associated with a carrieraggregation configuration or a dual connectivity configuration (e.g.,when multiple serving cells have a suboptimal or non-ideal backhaullink). An eCC may also be configured for use in unlicensed spectrum orshared spectrum (e.g., where more than one operator is allowed to usethe spectrum). An eCC characterized by wide carrier bandwidth mayinclude one or more segments that may be utilized by UEs 115 that arenot capable of monitoring the whole carrier bandwidth or are otherwiseconfigured to use a limited carrier bandwidth (e.g., to conserve power).

In some cases, an eCC may utilize a different symbol duration than otherCCs, which may include use of a reduced symbol duration as compared withsymbol durations of the other CCs. A shorter symbol duration may beassociated with increased spacing between adjacent subcarriers. Adevice, such as a UE 115 or base station 105, utilizing eCCs maytransmit wideband signals (e.g., according to frequency channel orcarrier bandwidths of 20, 40, 60, 80 MHz, etc.) at reduced symboldurations (e.g., 16.67 microseconds). A TTI in eCC may consist of one ormultiple symbol periods. In some cases, the TTI duration (that is, thenumber of symbol periods in a TTI) may be variable.

Wireless communications systems such as an NR system may utilize anycombination of licensed, shared, and unlicensed spectrum bands, amongothers. The flexibility of eCC symbol duration and subcarrier spacingmay allow for the use of eCC across multiple spectrums. In someexamples, NR shared spectrum may increase spectrum utilization andspectral efficiency, specifically through dynamic vertical (e.g., acrossthe frequency domain) and horizontal (e.g., across the time domain)sharing of resources.

In some aspects, a base station 105 may configure a UE 115 with a set ofCCEs of a control channel within a time duration, such as a slot.Additionally, the base station 105 may configure a plurality of searchspace set occasions, the plurality of search space set occasionsassociated with one or more search space sets comprising sets of controlchannel candidates for BD or CCEs for channel estimation. In some cases,due to BD and CCE channel estimation limitations, some control channelcandidates (e.g., PDCCH candidates) of one or more search space sets maybe dropped or pruned for blind decoding and/or CE purposes. Further,when operating in CA mode, a CA limit may correspond to a total numberof configurable control channel candidates across multiple CCs. A per-CClimit of control channel candidates may correspond to a number ofconfigurable control channel candidates for each CC. An applied set ofcontrol channel candidates may be determined by allocating controlchannel candidates across the multiple CCs based on the CA limit and theper-CC limit. Such techniques may be used in cases where the CCs have asame numerology or mixed numerology, and may also be used forcross-carrier scheduling.

FIG. 2 illustrates an example of a wireless communications system 200that supports search space design with overbooking in carrieraggregation in accordance with aspects of the present disclosure. Insome examples, wireless communications system 200 may implement aspectsof wireless communications system 100. Wireless communications system200 may include base station 105-a and UE 115-a, which may be examplesof a base station 105 and a UE 115 described with reference to FIG. 1.In some examples, base station 105-a may be in communication with one ormore UEs 115 within geographic coverage area 110-a. In this example,wireless communications system 200 may support carrier aggregation, andbase station 105-a may communicate with UE 115-a on resources ofmultiple component carriers 205, including a first component carrier205-a, a second component carrier 205-b, through an n-th componentcarrier 205-n.

As indicated above, various aspects of the present disclosure providetechniques for search space design with overbooking in CA, in whichcontrol channel candidates may be allocated across CCs 205 such that aper-CC limit and CA limit on the number of blind decodes or channelestimations to be performed by the UE 115-a are within its capability.The base station 105-a may configure search space sets according tocontrol channel candidates (e.g., Physical Downlink Control Channel(PDCCH) 210 candidates) at one or more aggregation levels to use forthese DCI transmissions. When configuring a search space set, the basestation may determine a control resource set (CORESET) containing thesearch space set. This CORESET may include a number of control channelelements (CCEs) and the search space set may be mapped to a CCE spacecorresponding to a subset of CCEs of the CORESET. The UE 115-a mayidentify this search space set configuration, and may monitor the CCEscorresponding to the control channel candidates for any DCItransmissions from the base station 105-a. A control region may be asearch space monitoring occasion for one or more search space sets thathas a common reference signal configuration (e.g., shares a scramblingsequence, etc.). The control channel candidates may correspond tolocations for control channel processing objects for BD or CCEs forchannel estimation.

As discussed above, in some cases, due to BD and CCE channel estimationlimitations, some control channel candidates (e.g., PDCCH 210candidates) of one or more search space sets may need to be dropped orpruned for blind decoding and/or CE purposes. When using CA, the UE115-a may be configured with a number of CCs 205. In some cases, the UE115-a may support CA with up to four downlink CCs 205 with the samenumerology, thus providing a maximum number of PDCCH 210 blind decodesper slot of the UE shall support is a product of the maximum number ofCCs (e.g., 4) and a number of configurable control channel candidatesfor BD. Similar maximums may apply to CCEs for channel estimation. Insome cases, the number of configurable control channel candidates may bedefined based on a sub-carrier spacing (SCS) of a CC 205 (e.g., {44, 36,22, 20} for SCS={15 kHz, 30 kHz, 60 kHz, 120 kHz} for BD, and {56, 56,48, 32} for SCS={15 kHz, 30 kHz, 60 kHz, 120 kHz} for CCE). In somecases, the UE 115-a may be capable of supporting more than four CCs 205,up to Y CCs of the same numerology, and such a UE 115-a may support amaximum number of PDCCH blind decodes that is a product of Y and anumber of configurable control channel candidates. In some cases, thevalue of Y is an integer and may be reported as a UE capability to thenetwork. As discussed above, overbooking may allow more configurablecontrol channel candidates than the UE 115-a can support, and candidateswithin search space (SS) sets may be mapped to meet the UE 115-acapability. If all candidates in a SS set are not able to be mapped,candidates in the SS set and in any subsequent SS sets may be droppedand not mapped. In some cases, mapping rules may be established betweenthe UE 115-a and the base station 105-a such that the same candidatesare identified. Additionally, a maximum number of CORESETs per bandwidthpart (BWP) may be defined (e.g., 3), and in some cases, a maximum of 10search space sets per BWP per cell may be defined.

In some cases, the UE 115-a may be configured with a search spaceconfiguration by UE-specific RRC signaling which includes following:CORESET ID (range: 0-11, to indicate which CORESET the search space ismapped to), wherein the search space can be associated with any CORESETconfiguration, and in some cases when the CORSET ID is UE-specificallyconfigured to be 0 it is mapped to the one configured by PBCH; and asearch space ID (range: 0-39), and in some cases, when the search spaceID is UE-specifically configured to be 0 it is mapped to the oneconfigured by PBCH.

When multiple CCs 205 are configured, as indicated above, the totalnumber of BD/CCE, which may correspond to a total number of controlchannel candidates, for of all CCs 205 should not exceed a CA limit.Further, the number of BD/CCE per scheduled CC 205 should not exceed thesingle carrier limit, thus a per-CC limit may be identified as a limitbased on a single carrier. In some cases, for cross-carrier scheduling,a lump sum of BD/CCE per CC limit may be assigned to the scheduling CC,as will be discussed in more detail below. In some cases, there is nooverbooking for a common search space (CSS), and thus overbookingtechniques may be applied to UE-specific search spaces (DESS).

As indicated, a per-CC limit may be defined, as well as a CA limit. Insome cases, if the number of BD/CCE for any scheduled CC 205 does notexceed the single carrier per-CC limit, the CA limit will also besatisfied. Then, CA overbooking handling simply becomes the singlecarrier overbooking handling of each CC based on corresponding singlecarrier limit. Thus, in cases where the scheduled CCs 205 are less thanor equal to four, or greater than four but less than or equal to the UE115-a capability, CA overbooking may be handled on a per-CC basis. Inthe other cases, the number of scheduled CCs 205 may exceed the UE 115-acapability, and thus satisfying the single carrier per-CC limit on allCCs 205 does not necessarily result in the CA limit being satisfied, andvarious techniques as discussed herein may allocate control channelcandidates across the scheduled CCs 205 to comply with the per-CC limitand the CA limit. In some cases, such overbooking handling may includereducing the number of CCs 205 that may be used for PDCCH 210 schedulingto be less than or equal to the UE 115-a capability, or less than orequal to four. In other cases, the per-CC limit may be reduced such thatit is smaller than the single carrier limit and such that a summation ofthe reduced per-CC limits is no larger than CA limit.

In some cases, the base station 105-a and UE 115-a may performoverbooking handling for each CC 205 separately based on the per-CClimit and, as long as per-CC limit is satisfied, the CA limit issatisfied, which may be referred to as independent overbooking handling.In other cases, the base station 105-a and UE 115-a may performoverbooking handling for each CC 205 based on single carrier limit andCA limit, which may be referred to as joint overbooking handling.

In cases that use independent overbooking handling, a number of CCs 205that are configured by network may be referred to as K, a UE capabilityfor the number of CCs may be referred to as M, a single carrier limitfor BE or CCE may be X, and a bandwidth of each CC c may be BW_(c). Insome cases, the bandwidth may be the CORESET bandwidth of one ormultiple CORESETs configured to the BWP, active BWP bandwidth, or cellbandwidth. In such cases, the BD or CCE number of the configured PDCCHs210 on a CC c is x_(c). As mentioned above, in cases where K is lessthan four or less than M, the per-CC limit may be utilized for each CC205. In cases, where K is greater than M, the CA limit may bedistributed among the CCs 205 to provide that the CA limit is notexceeded. Table 1 and Table 2 below provide a number of exemplarydistribution techniques. In any of the cases where the CA limit isdistributed, the UE 115-a and base station 105-a can optionally firstreduce the number of CCs 205 that can be scheduled with PDCCH 210, thendistribute CA limit among CCs, or keep per per-CC limit the same assingle carrier limit for some CCs (e.g., a primary cell (PCell) orprimary secondary cell (PSCell)), and distribute the remaining limitamong the other CCs.

TABLE 1 Independent Overbooking Handling Number of CCs Number scheduledof with Per CC limit {circumflex over (X)}_(c) CCs PDCCH for CC c Note K≤ 4 K {circumflex over (X)}_(c) = X 4 < K ≤ K {circumflex over (X)}_(c)= X M K > M M {circumflex over (X)}_(c) = X Number of CCs that aremapped with PDCCH corresponds to (e.g., is limited by) UE capability forPDCCH. K ${\hat{X}}_{c} = \frac{M \cdot X}{K}$ Even distribution. K${\hat{X}}_{c} = \frac{M \cdot X \cdot {BW}_{c}}{\sum_{n = 0}^{K - 1}{BW}_{n}}$BW proportional distribution. K${\hat{X}}_{c} = \frac{M \cdot X \cdot x_{c}}{\sum_{n = 0}^{K - 1}x_{n}}$Configuration proportional distribution, distribution changes from slotto slot

Such techniques for provide a number of options for distribute the CAlimit of BD or CCE among CCs 205 so that the total number of BD or CCEdoes not exceed the CA limit as long as each CC 205 does not exceed theper-CC limit. In cases where K>M options may be generalized by the belowformula where the per-CC limit for CC c can be defined by a set ofnon-negative numbers α_(c), c=0, 1 . . . , K−1

{circumflex over (X)} _(c)=α_(c) ·M·X.

In some cases, the set of non-negative numbers α_(c), c=0, 1 . . . , K−1satisfies the condition that Σ_(c=0) ^(K-1) α_(c)=1. Additionally, insome cases, the set of non-negative numbers α_(c), c=0, 1 . . . , K−1optionally satisfies the additional contention α_(c)≤1/M for any c.Table 2 provides, for such cases, {circumflex over (X)}_(c) for variousvalues of α_(c) in accordance with the above equation.

TABLE 2 Independent Overbooking Handling Number of CCs Number ofscheduled with Per CC limit {circumflex over (X)}_(c) for CCs PDCCH CC cValues of α_(c), c = 0, 1, . . . , K K > M M {circumflex over (X)}_(c) =X α_(c) = 1/M for c = 0, 1, . . . M − 1; α_(c) = 0 for c = M − 1, . . ., K − 1 K ${\hat{X}}_{c} = \frac{M \cdot X}{K}$ α_(c) = 1/K for c = 0,1, . . . K − 1; K${\hat{X}}_{c} = \frac{M \cdot X \cdot {BW}_{c}}{\sum_{n = 0}^{K - 1}{BW}_{n}}$${\alpha_{c} = {{\frac{{BW}_{c}}{\sum_{n = 0}^{K - 1}{BW}_{n}}{for}\mspace{14mu} c} = 0}},1,{{{\ldots \mspace{14mu} K} - 1};}$K${\hat{X}}_{c} = \frac{M \cdot X \cdot x_{c}}{\sum_{n = 0}^{K - 1}x_{n}}$${\alpha_{c} = {{\frac{x_{c}}{\sum_{n = 0}^{K - 1}x_{n}}{for}\mspace{14mu} c} = 0}},1,{{{\ldots \mspace{14mu} K} - 1};}$

As indicated above, in any of the cases where the CA limit isdistributed across CCs 205, the UE 115-a and base station 105-a mayoptionally first reduce the number of CCs 205 that can be scheduled withPDCCH 210, then distribute CA limit among CCs. A CC 205 is not scheduledwith PDCCH 210 if the corresponding α_(c) is set to 0. In some cases,the UE 115-a and base station 105-a may keep the per CC limit the sameas single carrier limit (X) for some CCs (e.g., PCell/PSCell), anddistribute the remaining limit among the other CCs. A CC's 205 per-CClimit ({circumflex over (X)}_(c)) can be set equal to single carrierlimit (X) if the corresponding α_(c)=1/M for this CC.

As can be seen from Tables 1 and 2, if the number of CCs (K) is four orless, the CA limit is satisfied as long as number of BD/CCE per CC doesnot exceed the single carrier limit (X). Further, if the number of CCs(K) is greater than four but does not exceed the UE 115-a capability(M), the number of BD/CCE per CC may not (e.g., should not) exceed thesingle carrier limit (X), and in such case the total number of BD/CCE ofall CCs will not exceed the CA limit. However, if the number of CCs (K)is greater than the UE 115-a capability (M), then the number of CCs thatcan be configured with PDCCH may be reduced to the UE capability; the CAlimit may be evenly distribution among all CCs

$\left( {{\hat{X}}_{c} = \frac{M \cdot X}{K}} \right),$

the CA limit may be distributed based on a fixed proportion among CCs,such as based on BW of CCs

$\left( {{\hat{X}}_{c} = \frac{M \cdot X \cdot {BW}_{c}}{\sum\limits_{n = 0}^{K - 1}{BW}_{n}}} \right),$

or the CA limit may be distributed based on a proportional distributionof the CA limit among all CCs 205 based on a BD/CCE number configured toeach CC

$\left( {{\hat{X}}_{c} = \frac{M \cdot X \cdot x_{c}}{\sum\limits_{n = 0}^{K - 1}x_{n}}} \right),$

Such techniques may be applied for CCs 205 having a same numerology orhaving a different numerology as will be discussed in more detail below.In some case, such techniques may be used in cross-carrier scheduling,as will also be discussed in more detail below.

In other cases, rather than distributing BDs/CCEs, overbooking handlingmay allow overbooking only for some CCs 205 and not allow overbookingfor other CCs 205. In such examples, for CCs that are allowed to beoverbooked, their PDCCH configuration is allowed to exceed the per-CClimit, and the base station 105-a and UE 115-a may perform overbookinghandling to trim the PDCCH configuration so that the mapped PDCCHs forthe CC do not exceed the per-CC limit and CA limit. In such examples,for CCs 205 that are not allowed to be overbooked, their PDCCHconfiguration is not allowed to exceed the per-CC limit. As long as CCs205 that are allowed to be overbooked do not exceed their per-CC limit,mapping of CCs 205 that are not allowed to be overbooked will not exceedthe CA limit. In some cases, one or more CCs 205, which may be a subsetof the total number of CCs 205, may be indicated as allowed to beoverbooked. In some cases, only a PCC and/or PSCC may be allowed to beoverbooked, and remaining CCs 205 may not be overbooked. Once thecontrol channel candidates are allocated to the CCs 205, mapping ofBDs/CCEs to the control channel candidates may be performed.

FIG. 3 illustrates an example of a BD/CCE mapping 300 that supportssearch space design with overbooking in carrier aggregation inaccordance with aspects of the present disclosure. In some examples,BD/CCE mapping 300 may implement aspects of wireless communicationssystem 100. In this example, a CC index 305 may correspond to an indexvalue for each CC, and a SS set index 310 may correspond to an index ofa SS set of a number of different SS sets that may be configured.

In some cases, mapping of SS sets of each CC, from the lowest CC indexto the highest CC index, may be performed. In such cases, mapping may bestopped for a CC if the per-CC limit is reached or if the CC is fullymapped. In such cases, for each CC, a number may indicate how many SSsets of the CC are mapped. In other cases, mapping of CCs associatedwith each SS set, from the lowest SS set index to the highest SS setindex, may be performed. In such cases, the mapping may skip a CC if theper-CC limit is reached or the CC is fully mapped. In such cases, onenumber may indicate how many SS sets are fully mapped, and one numbermay indicate how many CCs are mapped for the partially mapped SS set.Such mapping based on the per-CC limits that are obtained as discussedabove, provides that there is no need to check the CA limit whilemapping. For self-carrier scheduling, these two options above give samemapping result. For cross-carrier scheduling, more candidates may getmapped to a larger CC index due to CCE/BD reuse. In some cases,cross-carrier scheduling may not allow CCE/BD reuse among CCs for CAoverbooking.

As indicated above, in some cases, joint overbooking handling of CCs maybe used. In such cases, if the number of CCs exceeds the UE capability,overbooking handling may be performed for each CC based on the singlecarrier limit and CA limit. Again, in such cases, there are twodimensions to sweep in mapping, namely the CC index 305 and SS set index310. In some cases, all SS sets of each CC may be mapped from the lowestCC index to the highest CC index. In such cases, mapping may be stoppedfor a CC if the single carrier limit is reached or the CC is fullymapped. Further, mapping may be stopped for any CC if the CA limit isreached. For each CC, a number indicates how many search space sets ofthe CC are mapped.

In other cases, all CCs associated with a SS set may be mapped from thelowest SS set index to the highest SS set index. In such cases, a CC maybe skipped if the single carrier limit is reached or the CC is fullymapped. Further, mapping may be stopped for any CC associated with anySS set if the CA limit is reached. One number may indicate how many SSsets are fully mapped, and one number to indicate how many CCs aremapped for the partially mapped SS set. In either of these mappingcases, the number of CCs that can be scheduled with PDCCH is unknownbefore mapping is finished.

FIG. 4 illustrates an example of a mixed numerology CC configuration 400that supports search space design with overbooking in carrieraggregation in accordance with aspects of the present disclosure. Insome examples, mixed numerology CC configuration 400 may implementaspects of wireless communications system 100. In this example, a firstCC 405 (CC0) may have a 60 kHz SCS, a second CC 410 (CC1) may have a 30kHz SCS, and a third CC 415 (CC2) may have a 15 kHz SCS. Such differentSCSs thus provide that each CC 405-415 has a slot with a differentduration, and various techniques may provide overbooking handling forsuch mixed numerology cases.

In some cases, a common slot may be defined and CA limits may bedetermined based on the common slot. In some cases, the need of a commonslot may be avoided by converting the CA limit/overbooking into per CClimit/overbooking. In other cases, a reference SCS may be identified,and the corresponding reference slot may be the common slot. The CAlimit in such mixed numerology cases and overbooking handling may beperformed using similar techniques as discussed above with respect toFIGS. 2 and 3, as will be discussed in more detail below. Further, insome cases, cross-carrier scheduling may be implemented, in which ascheduling CC may schedule one or more other CCs that may have adifferent SCS.

FIG. 5 illustrates an example of cross-carrier scheduling 500 thatsupports search space design with overbooking in carrier aggregation inaccordance with aspects of the present disclosure. In some examples,cross-carrier scheduling 500 may implement aspects of wirelesscommunications system 100. In this example, a first CC 505 (CC0) may bea scheduling CC and scheduling DCI 510 may be used to schedule a secondCC 515 (CC1). Similarly, a third CC 520 (CC2) may be a scheduling CC andscheduling DCI 525 may be used to schedule a fourth CC 530 (CC3).

In some cases, for cross-carrier scheduling, the CA limit can be definedbased on the scheduling CC's SCS. In such cases, if there is onescheduling CC, the mixed numerology CA may be treated as same numerologyCA with SCS equal to the scheduling CC's SCS. Such treatment is logicalbecause PDCCH decoding occurs in the scheduling CC. In cases with two ormore scheduling CCs, scheduled CCs may use the SCS of the scheduling CC.Using such techniques, overbooking handling may be performed in asimilar manner as discussed above for self-carrier scheduling. In theexample of FIG. 5, the first CC 505 may have a first SCS of 15 kHz, andthe second CC 515 may have a second SCS of 30 kHz. Further, the third CC520 may have a third SCS of 60 kHz, and the fourth CC 530 may have afourth SCS of 120 kHz. In such cases, BD/CCE limits and handling ofoverbooking may be performed as if the first CC 505 and second CC 515both have the first SCS of 15 kHz, and as if the third CC 520 and fourthCC 530 both have the third SCS of 60 kHz.

Using such SCS assignments, overbooking handling may be performed in asimilar manner as discussed above. For example, for independentoverbooking handling of CCs, again the number of CCs is K, UE capabilityis M, single carrier limit is X_(c), and bandwidth is BW_(c) for CC c.The BD/CCE number of the configured PDCCHs on CC c is x_(c). Asindicated above, for cross-carrier scheduling, the scheduled CC followsthe scheduling CC for per-CC and CA limits. Tables 3 and 4 below providea number of exemplary distribution techniques.

Again, similarly as discussed above, in any of the cases where the CAlimit is distributed, the UE and base station may optionally firstreduce the number of CCs that can be scheduled with PDCCH, thendistribute CA limit among remaining CCs, or may keep the per-CC limitsame as single carrier limit for some CCs, distribute the remaining CAlimit among the other CCs.

TABLE 3 Independent Overbooking Handling Number of CCs scheduled Numberwith Per CC limit for of CCs PDCCH CA {circumflex over (X)}_(c) Note K ≤4 K {circumflex over (X)}_(c) = X_(c) 4 < K ≤ K {circumflex over(X)}_(c) = X_(c) M K > M M {circumflex over (X)}_(c) = X_(c) Reducednumber of CCs K ${\hat{X}}_{c} = \frac{M \cdot X_{c}}{K}$ Evendistribution K${\hat{X}}_{c} = \frac{M \cdot X_{c} \cdot {BW}_{c}}{\sum_{n = 0}^{K - 1}{BW}_{n}}$BW proportional distribution K${\hat{X}}_{c} = \frac{M \cdot X_{c} \cdot x_{c}}{\sum_{n = 0}^{K - 1}x_{n}}$Configuration proportional distribution, distribution changes from slotto slot

Such techniques for provide a number of options for distribute the CAlimit of BD or CCE among CCs so that the total number of BD or CCE doesnot exceed the CA limit as long as each CC does not exceed the per-CClimit. In cases where K>M options may be generalized by the belowformula where the per-CC limit for CC c can be defined by a set ofnon-negative numbers α_(c), c=0, 1 . . . , K−1

{circumflex over (X)} _(c)=α_(c) ·M·X.

In some cases, the set of non-negative numbers α_(c), c=0, 1 . . . , K−1satisfies the condition that Σ_(c=0) ^(K-1) α_(c)=1. Additionally, insome cases, the set of non-negative numbers α_(c), c=0, 1 . . . , K−1optionally satisfies the additional contention α_(c)≤1/M for any c.Table 4 provides, for such cases, {circumflex over (X)}_(c) for variousvalues of α_(c) in accordance with the above equation.

TABLE 4 Independent Overbooking Handling Number of Number of CCsscheduled Per CC limit {circumflex over (X)}_(c) for CCs with PDCCH CC cValues of α_(c), c = 0, 1, . . . , K K > M M {circumflex over (X)}_(c) =X_(c) α_(c) = 1/M for c = 0, 1, . . . M − 1; α_(c) = 0 for c = M − 1, .. . , K − 1 K ${\hat{X}}_{c} = \frac{M \cdot X_{c}}{K}$ α_(c) = 1/K forc = 0, 1, . . . K − 1; K${\hat{X}}_{c} = \frac{M \cdot X_{c} \cdot {BW}_{c}}{\sum_{n = 0}^{K - 1}{BW}_{n}}$${\alpha_{c} = {{\frac{{BW}_{c}}{\sum_{n = 0}^{K - 1}{BW}_{n}}{for}\mspace{14mu} c} = 0}},1,{{{\ldots \mspace{14mu} K} - 1};}$K${\hat{X}}_{c} = \frac{M \cdot X_{c} \cdot x_{c}}{\sum_{n = 0}^{K - 1}x_{n}}$${\alpha_{c} = {{\frac{x_{c}}{\sum_{n = 0}^{K - 1}x_{n}}{for}\mspace{14mu} c} = 0}},1,{{\ldots \mspace{14mu} K} - {1\text{;}}}$

As indicated by tables 3 and 4, the CA limit can be described by anumber K, if number of CCs does not exceed four, or does not exceed theUE capability. Further, a summation of per-CC limits normalized by thecorresponding single carrier limit satisfies

${\sum\limits_{c = 0}^{K - 1}\frac{{\hat{X}}_{c}}{X_{c}}} = {K.}$

The CA limit can be described by a number M, if number of CCs exceedsthe UE capability, and a summation of per CC limits normalized by thecorresponding single carrier limit satisfies

${\sum\limits_{c = 0}^{K - 1}\frac{{\hat{X}}_{c}}{X_{c}}} = {M.}$

As can be seen from Tables 1 and 2, if the number of CCs (K) is four orless, the CA limit is satisfied as long as number of BD/CCE per CC doesnot exceed the single carrier limit (X). Further, if the number of CCs(K) is greater than four but does not exceed the UE capability (M), thenumber of BD/CCE per CC should not exceed the single carrier limit (X),and in such case the total number of BD/CCE of all CCs will not exceedthe CA limit. However, if the number of CCs (K) is greater than the UEcapability (M), then the number of CCs that can be configured with PDCCHmay be reduced to the UE capability; the CA limit may be evenlydistribution among all CCs

$\left( {{\hat{X}}_{c} = \frac{M \cdot X_{c}}{K}} \right),$

the CA limit may be distributed based on a fixed proportion among CCs,such as based on BW of CCs

$\left( {{\hat{X}}_{c} = \frac{M \cdot X \cdot {BW}_{c}}{\sum\limits_{n = 0}^{K - 1}{BW}_{n}}} \right),$

or the CA limit may be distributed based on a proportional distributionof the CA limit among all CCs based on a BD/CCE number configured toeach CC

$\left( {{\hat{X}}_{c} = \frac{M \cdot X \cdot x_{c}}{\sum\limits_{n = 0}^{K - 1}x_{n}}} \right).$

Thus, overbooking handling of CA can be performed by single carrieroverbooking handling of each CC in the same way as the same numerologyCA discussed above.

FIG. 6 illustrates an example of a mixed numerology reference slot 600that supports search space design with joint overbooking in carrieraggregation in accordance with aspects of the present disclosure. Insome examples, mixed numerology reference slot 600 may implement aspectsof wireless communications system 100. In this example, a first CC 605(CC0) may have a 60 kHz SCS, a second CC 610 (CC1) may have a 30 kHzSCS, and a third CC 615 (CC2) may have a 15 kHz SCS. Such different SCSsthus provide that each CC 605-615 has a slot with a different duration,and various techniques may provide overbooking handling for such mixednumerology cases.

In cases where joint overbooking is used for mixed numerology CCs, areference SCS may be selected, and a per slot limit may be defined basedon a reference slot 620 of the reference SCS. In the example, of FIG. 6,the SCS of the second CC 610 may be selected as the reference SCS. Insuch cases, the per-CC limit may be the same as single carrier limit,and overbooking handling determines how many CCs can be mapped withPDCCH candidates. Limits may be determined, for example, by counting thenumber of BD/CCE within the reference slot 620 for each CC 605-615. Insuch cases, if the SCS of a CC is greater than or equal to the referenceSCS, the BD/CCE numbers of all slots of this CC that entirely overlapwith the reference slot may be summed. In the example, of FIG. 6, such asum would be N_(0,0)+N_(0,1) for the first CC 605, and N_(1,0) for thesecond CC 610. If the SCS of a CC is less than the reference SCS, theBD/CCE number of the slot of this CC that partially overlaps with thereference slot is scaled by the ratio of the corresponding CC SCS to thereference SCS. In the example of FIG. 6, this would be N_(2,0)/2 for thethird CC 615.

A total BD/CCE consumption of all CCs within the reference slot may thenbe calculated. For each CC, the BD/CCE number within reference slot maybe normalized by the corresponding single carrier limit and the numberof slots of this CC overlapping with the reference slot. If part of aslot of this CC overlaps with the reference slot, the number of slots ofthis CC overlapping with the reference slot is the percentage of theoverlapping part of the slot. For example, for the CC with SCS=15 kHz inFIG. 6, the number of slots that overlap with the reference slot is ½ or50%. Then, the total number may be calculated by summing up thenormalized number of all CCs. In the example, if FIG. 6, such a sumwould be

$\frac{N_{0,0} + N_{0,1}}{2*48} + \frac{N_{1,0}}{56} + {\frac{N_{2,0}}{56}.}$

Mapping may then be performed based on the BD/CCD number. Again, twodimensions may be swept, corresponding to a CC index and a SS set index.In some cases, all SS sets of each CC from the lowest CC index to thehighest CC index, in a reference slot, may be mapped. Mapping may bestopped for a CC in a slot of the CC if the single carrier limit isreached or the CC is fully mapped in the slot(s) of the CC thatpartially or fully overlap with the reference slot. Further, mapping CCsmay be stopped if the CA limit is reached. For each CC in such cases, anumber indicates how many search space sets of the CC are mapped in aslot of the CC. In other cases, all CCs associated with a SS set may bemapped from the lowest SS set index to the highest SS set index, in areference slot. In such cases, a CC may be skipped in a slot of the CCif single carrier limit is reached or the CC is fully mapped in slot(s)of each CC that overlaps partially or fully with the reference slot.Mapping may be stopped for any CC associated with any SS set if the CAlimit is reached. One number in such cases may indicate how many SS setsare fully mapped, and one number may indicate how many CCs are mappedfor the partially mapped SS set. The number of CCs that can be scheduledwith PDCCH is unknown before mapping is finished.

FIG. 7 illustrates an example of a mixed numerology reference slot 700that supports search space design with overbooking in carrieraggregation in accordance with aspects of the present disclosure. Insome examples, mixed numerology reference slot 700 may implement aspectsof wireless communications system 100. In this example, a first CC 705(CC0) may have a 60 kHz SCS, a second CC 710 (CC1) may have a 30 kHzSCS, and a third CC 715 (CC2) may have a 15 kHz SCS. Such different SCSsthus provide that each CC 705-715 has a slot with a different duration,and various techniques may provide overbooking handling for such mixednumerology cases.

In cases where joint overbooking is used for mixed numerology CCs,again, a reference SCS may be selected, and a per slot limit may definedbased on the reference SCS, which may provide a first reference slot 720and a second reference slot 725. In the example, of FIG. 7, the SCS ofthe second CC 710 may be selected as the reference SCS. In cases whereSCS of a CC is less than the reference SCS, a slot of this CC partiallyoverlaps with multiple reference slots of the reference SCS, as in theexample of the slot of the third CC 715 partially overlapping the firstreference slot 720. Mapping of the third CC 715 is performed in thefirst reference slot 720, namely N_(2,0) for the third CC 715 in thefirst reference slot 720. In other reference slots that overlap with theslot of the third CC 715, which is second reference slot 725 in theexample of FIG. 7, the BD/CCE consumption of the third CC 715 isdeducted from the CA limit before the other CCs are mapped, and thus thecontribution of N_(2,0) in the second reference slot 725 is deducted. Insome cases, the smallest SCS of configured CCs may be selected as thereference SCS, in order to avoid such partially overlapping slots.

FIG. 8 shows a block diagram 800 of a device 805 that supports searchspace design with overbooking in carrier aggregation in accordance withaspects of the present disclosure. The device 805 may be an example ofaspects of a UE 115 or base station 105 as described herein. The device805 may include a receiver 810, a communications manager 815, and atransmitter 820. The device 805 may also include a processor. Each ofthese components may be in communication with one another (e.g., via oneor more buses).

Receiver 810 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to search spacedesign with overbooking in carrier aggregation, etc.). Information maybe passed on to other components of the device 805. The receiver 810 maybe an example of aspects of the transceiver 1120 or 1220 as describedwith reference to FIGS. 11 and 12. The receiver 810 may utilize a singleantenna or a set of antennas.

The communications manager 815 may establish a wireless connection via aset of CCs using CA, communicate based on the applied set of controlchannel candidates, determine a CA limit corresponding to a total numberof configurable control channel candidates across the set of CCs, thecontrol channel candidates including BD candidates or CCE candidates forchannel estimation, determine a per-CC limit corresponding to a per-CCnumber of control channel candidates that are configurable for each CCof the set of CCs, and determine an applied set of control channelcandidates by allocating control channel candidates across a number ofconfigured control channel candidates of the set of CCs based on the CAlimit and the per-CC limit, where the number of configured controlchannel candidates for at least one of the CCs may exceed the per-CClimit.

The communications manager 815 may also establish a wireless connectionvia two or more CCs using CA, communicate based on the applied set ofcontrol channel candidates, identify a first subset of the two or moreCCs in which configured control channel candidates may exceed a per-CClimit of control channel candidates for each CC, the control channelcandidates corresponding to locations for control channel processingobjects for blind decoding (BD) or control channel elements (CCEs) forchannel estimation, identify a second subset of the two or more CCs inwhich the number of configured control channel candidates comply withthe per-CC limit of control channel candidates for each CC, anddetermine an applied set of control channel candidates for the firstsubset of CCs by mapping control channel candidates across the firstsubset of CCs such that mapped control channel candidates comply withthe per-CC limit. The communications manager 815 may be an example ofaspects of the communications manager 1110 or 1210 as described herein.

The communications manager 815, or its sub-components, may beimplemented in hardware, code (e.g., software or firmware) executed by aprocessor, or any combination thereof. If implemented in code executedby a processor, the functions of the communications manager 815, or itssub-components may be executed by a general-purpose processor, a DSP, anapplication-specific integrated circuit (ASIC), a FPGA or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described in the present disclosure.

The communications manager 815, or its sub-components, may be physicallylocated at various positions, including being distributed such thatportions of functions are implemented at different physical locations byone or more physical components. In some examples, the communicationsmanager 815, or its sub-components, may be a separate and distinctcomponent in accordance with various aspects of the present disclosure.In some examples, the communications manager 815, or its sub-components,may be combined with one or more other hardware components, includingbut not limited to an input/output (I/O) component, a transceiver, anetwork server, another computing device, one or more other componentsdescribed in the present disclosure, or a combination thereof inaccordance with various aspects of the present disclosure.

Transmitter 820 may transmit signals generated by other components ofthe device 805. In some examples, the transmitter 820 may be collocatedwith a receiver 810 in a transceiver module. For example, thetransmitter 820 may be an example of aspects of the transceiver 1120 or1220 as described with reference to FIGS. 11 and 12. The transmitter 820may utilize a single antenna or a set of antennas.

FIG. 9 shows a block diagram 900 of a device 905 that supports searchspace design with overbooking in carrier aggregation in accordance withaspects of the present disclosure. The device 905 may be an example ofaspects of a device 805, a UE 115, or a base station 105 as describedherein. The device 905 may include a receiver 910, a communicationsmanager 915, and a transmitter 945. The device 905 may also include aprocessor. Each of these components may be in communication with oneanother (e.g., via one or more buses).

Receiver 910 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to search spacedesign with overbooking in carrier aggregation, etc.). Information maybe passed on to other components of the device 905. The receiver 910 maybe an example of aspects of the transceiver 1120 or 1220 as describedwith reference to FIGS. 11 and 12. The receiver 910 may utilize a singleantenna or a set of antennas.

The communications manager 915 may be an example of aspects of thecommunications manager 815 as described herein. The communicationsmanager 915 may include a CA manager 920, a CA limit component 925, a CClimit component 930, a control channel candidate component 935, and a CCselection component 940. The communications manager 915 may be anexample of aspects of the communications manager 1110 or 1210 asdescribed herein.

The CA manager 920 may establish a wireless connection via a set of CCsusing CA and communicate based on the applied set of control channelcandidates.

The CA limit component 925 may determine a CA limit corresponding to atotal number of configurable control channel candidates across the setof CCs, the control channel candidates including BD candidates or CCEcandidates for channel estimation.

The CC limit component 930 may determine a per-CC limit corresponding toa per-CC number of control channel candidates that are configurable foreach CC of the set of CCs.

The control channel candidate component 935 may determine an applied setof control channel candidates by allocating control channel candidatesacross a number of configured control channel candidates of the set ofCCs based on the CA limit and the per-CC limit, where the number ofconfigured control channel candidates for at least one of the CCs mayexceed the per-CC limit. In some cases, the control channel candidatecomponent 935 may determine an applied set of control channel candidatesfor the first subset of CCs by mapping control channel candidates acrossthe first subset of CCs such that mapped control channel candidatescomply with the per-CC limit.

The CC selection component 940 may identify a first subset of the two ormore CCs in which configured control channel candidates may exceed aper-CC limit of control channel candidates for each CC, the controlchannel candidates corresponding to locations for control channelprocessing objects for BD or CCEs for channel estimation and identify asecond subset of the two or more CCs in which the number of configuredcontrol channel candidates comply with the per-CC limit of controlchannel candidates for each CC.

Transmitter 945 may transmit signals generated by other components ofthe device 905. In some examples, the transmitter 945 may be collocatedwith a receiver 910 in a transceiver module. For example, thetransmitter 945 may be an example of aspects of the transceiver 1120 or1220 as described with reference to FIGS. 11 and 12. The transmitter 945may utilize a single antenna or a set of antennas.

FIG. 10 shows a block diagram 1000 of a communications manager 1005 thatsupports search space design with overbooking in carrier aggregation inaccordance with aspects of the present disclosure. The communicationsmanager 1005 may be an example of aspects of a communications manager815, a communications manager 915, or a communications manager 1110described herein. The communications manager 1005 may include a CAmanager 1010, a CA limit component 1015, a CC limit component 1020, acontrol channel candidate component 1025, a CC selection component 1030,a search space set identifier 1035, a mapping component 1040, and areference SCS component 1045. Each of these modules may communicate,directly or indirectly, with one another (e.g., via one or more buses).

The CA manager 1010 may establish a wireless connection via a set of CCsusing CA. In some examples, the CA manager 1010 may communicate based onan applied set of control channel candidates.

The CA limit component 1015 may determine a CA limit corresponding to atotal number of configurable control channel candidates across the setof CCs, the control channel candidates including BD candidates or CCEcandidates for channel estimation. In some cases, the CA limit component1015 may control the number of configured control channel candidatesbased at least in part on a per-CA limit. As one example, the CA limitcomponent 1015 may control the number of configured control channelcandidates to comply with the per-CA limit of control channel candidatesfor two or more CCs from the set of CCs.

The CC limit component 1020 may determine a per-CC limit correspondingto a per-CC number of control channel candidates that are configurablefor each CC of the set of CCs. In some cases, the per-CC limit for eachCC of the set of CCs is defined by a set of non-negative numbers suchthat the per-CC limit is a product of a selected non-negative number,the first number of CCs, and a single carrier limit of control channelcandidates that are configurable for a single non-CA carrier, and wherethe selected non-negative number is based on whether a BD limit budgetor a CCE limit budget is distributed evenly, proportional to abandwidth, or proportional to configured control channel candidates, foreach CC. In some cases, a sum of the set of non-negative numbersselected for each CC of the set of CCs equals one. In some cases, eachnon-negative number is less than or equal to one divided by the firstnumber of CCs.

The control channel candidate component 1025 may determine an appliedset of control channel candidates by allocating control channelcandidates across a number of configured control channel candidates ofthe set of CCs based on the CA limit and the per-CC limit, where thenumber of configured control channel candidates for at least one of theCCs may exceed the per-CC limit. In some examples, the control channelcandidate component 1025 may determine an applied set of control channelcandidates for the first subset of CCs by mapping control channelcandidates across the first subset of CCs such that mapped controlchannel candidates comply with the per-CC limit. In some examples, thecontrol channel candidate component 1025 may allocate control channelcandidates separately for each CC of the set of CCs, the control channelcandidates for each CC allocated to comply with the per-CC limit.

In some examples, the control channel candidate component 1025 maydistribute a BD limit budget or a CCE limit budget evenly across thesecond number of CCs, where a portion of the BD limit budget or the CCElimit budget for each CC corresponds to a product of the first number ofCCs and the per-CC limit divided by the second number of CCs. In someexamples, the control channel candidate component 1025 may distribute aBD limit budget or a CCE limit budget across the second number of CCsaccording to a bandwidth-proportional distribution, where a portion ofthe BD limit budget or the CCE limit budget for each CC corresponds to aproduct of the first number of CCs, the per-CC limit, and a bandwidth ofthe associated CC, divided by a total cumulative bandwidth of the secondnumber of CCs. In some examples, the control channel candidate component1025 may bandwidth of the associated CC corresponds to a bandwidth of anumber of control resource sets (CORESETs), an active bandwidth part(BWP), or a cell bandwidth of the associated CC. In some examples, thecontrol channel candidate component 1025 may distribute a BD limitbudget or a CCE limit budget across the second number of CCs accordingto a slot-based proportional distribution, where a portion of the BDlimit budget or the CCE limit budget for each CC corresponds to aproduct of the first number of CCs, the per-CC limit, and a number ofBDs or CCEs associated with the configured control channel candidates ofthe associated CC for an associated slot, divided by a total cumulativenumber of configured control channel candidates of the second number ofCCs.

In some examples, the control channel candidate component 1025 mayallocate control channel candidates jointly for the set of CCs, thecontrol channel candidates for each CC allocated to comply with theper-CC limit and the CA limit. In some examples, the control channelcandidate component 1025 may allocate a BD limit budget or a CCE limitbudget separately for each CC of the set of CCs based on control channelcandidates for each CC that are allocated to comply with the per-CClimit. In some cases, a UE is capable of supporting a first number ofCCs, and where a second number of CCs in the set of CCs is less than orequal to the first number of CCs, and where the control channelcandidates for each CC are separately allocated to each comply with theper-CC limit. In some cases, a UE is capable of supporting a firstnumber of CCs, and where a second number of CCs in the set of CCs isgreater than the first number of CCs.

The CC selection component 1030 may identify a first subset of the twoor more CCs in which configured control channel candidates may exceed aper-CC limit of control channel candidates for each CC, the controlchannel candidates corresponding to locations for control channelprocessing objects for blind decoding (BD) or control channel elements(CCEs) for channel estimation. In some examples, the CC selectioncomponent 1030 may allocate control channel candidates across the subsetof CCs, where the control channel candidates for each CC of the subsetof CCs are separately allocated to each comply with the per-CC limit.

In some examples, the CC selection component 1030 may identify a secondsubset of the two or more CCs in which the number of configured controlchannel candidates comply with the per-CC limit of control channelcandidates for each CC. In some examples, the CC selection component1030 may select a subset of CCs from the set of CCs, the subset of CCshaving a third number of CCs corresponding to the first number of CCs.In some examples, the CC selection component 1030 may reduce a number ofCCs of the set of CCs that can be scheduled with control channeltransmissions to correspond to the second number of CCs, anddistributing a BD limit budget or a CCE limit budget across configuredcontrol channel candidates of the reduced number of CCs. In someexamples, the CC selection component 1030 may maintain the per-CC limitfor a first subset of CCs and distributing remaining of the CA limitcontrol channel candidates among remaining CCs of the set of CCs.

In some cases, the set of CCs includes at least a first CC having afirst sub-carrier spacing (SCS) and a second CC having a second SCS thatis different than the first SCS. In some cases, the first CC is ascheduling CC that provides scheduling information for each of the CCsof the set of CCs, and where the first SCS is used in determining the CAlimit for the scheduling CC and each of the CCs of the set of CCs thatis provided scheduling information. In some cases, the first SCS is usedfor the second CC for determining the applied set of control channelcandidates.

In some cases, the first subset of the two or more CCs includes aprimary component carrier (PCC), a primary secondary component carrier(PSCC) and the second subset of the two or more CCs includes one or moresecondary component carriers (SCCs). In some cases, the two or more CCsincludes at least a first CC having a first sub-carrier spacing (SCS),and a primary secondary component carrier (PSCC) and a second CC havinga second SCS that is different than the first SCS. In some cases, a PCCmay be also called “a primary cell” or “PCell.” In some cases, a networkmay configure a cell as a PCell when dual connectivity (DC) isconfigured or when DC is not configured. When DC is configured, thePCell may be configured in a master cell group (MCG). In some cases, thePSCC may be known as “a primary secondary cell” or “PSCell.” In somecases, a PSCell may be configured to be “on” when a network configuresdual connectivity. In some cases, a PSCell may be configured in asecondary cell group (SCG).

The search space set identifier 1035 may identify a set of search space(SS) sets that indicate, for each CC of the set of CCs, associatedresources for available control channel candidates. In some examples,the search space set identifier 1035 may identify set of search space(SS) sets that each indicate associated resources for available controlchannel candidates for two or more CCs, where each CC set has a SS setindex. In some examples, the search space set identifier 1035 mayidentify a set of search space (SS) sets that indicate, for each CC ofthe set of CCs, associated resources for available control channelcandidates.

The mapping component 1040 may map the set of SS sets of each CC of theset of CCs up to the per-CC limit to determine the applied set ofcontrol channel candidates for the corresponding CC, where each CC ofthe set of CCs has an ordered CC index, and where the mapping is from alowest CC index to a highest CC index. In some examples, the mappingcomponent 1040 may map the each CC associated with each SS set todetermine the applied set of control channel candidates for thecorresponding SS set, where a control channel candidate for a CC isskipped if the per-CC limit for the corresponding CC is reached or theCC is fully mapped, and where the mapping is from a lowest SS index to ahighest SS index.

In some examples, the mapping component 1040 may maintain a cumulativecount of mapped control channel candidates across the set of CCs. Insome examples, the mapping component 1040 may stop the mapping if thecumulative count reaches the CA limit.

In some examples, the mapping component 1040 may map the each CCassociated with each SS set to determine the applied set of controlchannel candidates for the corresponding SS set, where a control channelcandidate for a CC is skipped if the per-CC limit for the correspondingCC is reached or the CC is fully mapped, and where the mapping is from alowest SS index to a highest SS index. In some examples, the mappingcomponent 1040 may maintain a cumulative count of mapped control channelcandidates across the set of SS sets. In some cases, a number of CCs ofthe set of CCs that can be scheduled with control channel candidates isunknown until the allocating is finished.

The reference SCS component 1045 may identify the first SCS as areference SCS and identify a reference slot duration based on thereference SCS. In some examples, the reference SCS component 1045 maydetermine a second slot duration of the second CC based on the secondSCS. In some examples, the reference SCS component 1045 may determinethe per-CC limit of the second CC based on the second slot durationrelative to the reference slot duration. In some examples, the referenceSCS component 1045 may allocate control channel candidates jointly forthe set of CCs, the control channel candidates for each CC allocated tocomply with the per-CC limit and the CA limit. In some examples, thereference SCS component 1045 may count a number of control channelcandidates for each reference slot duration for each CC. In someexamples, the reference SCS component 1045 may calculate a total numberof control channel candidates for each CC in the reference slotduration. In some examples, the reference SCS component 1045 mayallocate a set of BDs or CCEs to the total number control channelcandidates for each CC to comply with the per-CC limit and the CA limit.In some cases, a smallest SCS of the first SCS and the second SCS isselected as the reference SCS.

In some cases, the first SCS is smaller than the second SCS, the secondSCS is the reference SCS, and first slot duration of the first CC islonger than the reference slot duration, and where the total number ofcontrol channel candidates for each CC in the reference slot duration isadjusted based a portion of the first slot duration that overlaps withthe subsequent reference slot duration.

FIG. 11 shows a diagram of a system 1100 including a device 1105 thatsupports search space design with overbooking in carrier aggregation inaccordance with aspects of the present disclosure. The device 1105 maybe an example of or include the components of device 805, device 905, ora UE 115 as described herein. The device 1105 may include components forbi-directional voice and data communications including components fortransmitting and receiving communications, including a communicationsmanager 1110, a transceiver 1120, an antenna 1125, memory 1130, aprocessor 1140, and an I/O controller 1150. These components may be inelectronic communication via one or more buses (e.g., bus 1155).

The communications manager 1110 may establish a wireless connection viaa set of component carriers (CCs) using carrier aggregation (CA),communicate based on the applied set of control channel candidates,determine a CA limit corresponding to a total number of configurablecontrol channel candidates across the set of CCs, the control channelcandidates including blind decoding (BD) candidates or control channelelement (CCE) candidates for channel estimation, determine a per-CClimit corresponding to a per-CC number of control channel candidatesthat are configurable for each CC of the set of CCs, and determine anapplied set of control channel candidates by allocating control channelcandidates across a number of configured control channel candidates ofthe set of CCs based on the CA limit and the per-CC limit, where thenumber of configured control channel candidates for at least one of theCCs may exceed the per-CC limit. The communications manager 1110 mayalso establish a wireless connection via two or more component carriers(CCs) using carrier aggregation (CA), communicate based on the appliedset of control channel candidates, identify a first subset of the two ormore CCs in which configured control channel candidates may exceed aper-CC limit of control channel candidates for each CC, the controlchannel candidates corresponding to locations for control channelprocessing objects for blind decoding (BD) or control channel elements(CCEs) for channel estimation, identify a second subset of the two ormore CCs in which the number of configured control channel candidatescomply with the per-CC limit of control channel candidates for each CC,and determine an applied set of control channel candidates for the firstsubset of CCs by mapping control channel candidates across the firstsubset of CCs such that mapped control channel candidates comply withthe per-CC limit.

Transceiver 1120 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1120 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1120 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1125.However, in some cases the device may have more than one antenna 1125,which may be capable of concurrently transmitting or receiving multiplewireless transmissions.

The memory 1130 may include RAM, ROM, or a combination thereof. Thememory 1130 may store computer-readable code 1135 including instructionsthat, when executed by a processor (e.g., the processor 1140) cause thedevice to perform various functions described herein. In some cases, thememory 1130 may contain, among other things, a BIOS which may controlbasic hardware or software operation such as the interaction withperipheral components or devices.

The processor 1140 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 1140 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into the processor 1140. The processor 1140 may beconfigured to execute computer-readable instructions stored in a memory(e.g., the memory 1130) to cause the device 1105 to perform variousfunctions (e.g., functions or tasks supporting search space design withoverbooking in carrier aggregation).

The I/O controller 1150 may manage input and output signals for thedevice 1105. The I/O controller 1150 may also manage peripherals notintegrated into the device 1105. In some cases, the I/O controller 1150may represent a physical connection or port to an external peripheral.In some cases, the I/O controller 1150 may utilize an operating systemsuch as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, oranother known operating system. In other cases, the I/O controller 1150may represent or interact with a modem, a keyboard, a mouse, atouchscreen, or a similar device. In some cases, the I/O controller 1150may be implemented as part of a processor. In some cases, a user mayinteract with the device 1105 via the I/O controller 1150 or viahardware components controlled by the I/O controller 1150.

The code 1135 may include instructions to implement aspects of thepresent disclosure, including instructions to support wirelesscommunications. The code 1135 may be stored in a non-transitorycomputer-readable medium such as system memory or other type of memory.In some cases, the code 1135 may not be directly executable by theprocessor 1140 but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

FIG. 12 shows a diagram of a system 1200 including a device 1205 thatsupports search space design with overbooking in carrier aggregation inaccordance with aspects of the present disclosure. The device 1205 maybe an example of or include the components of device 805, device 905, ora base station 105 as described herein. The device 1205 may includecomponents for bi-directional voice and data communications includingcomponents for transmitting and receiving communications, including acommunications manager 1210, a network communications manager 1215, atransceiver 1220, an antenna 1225, memory 1230, a processor 1240, and aninter-station communications manager 1245. These components may be inelectronic communication via one or more buses (e.g., bus 1255).

The communications manager 1210 may establish a wireless connection viaa set of component carriers (CCs) using carrier aggregation (CA),communicate based on the applied set of control channel candidates,determine a CA limit corresponding to a total number of configurablecontrol channel candidates across the set of CCs, the control channelcandidates including blind decoding (BD) candidates or control channelelement (CCE) candidates for channel estimation, determine a per-CClimit corresponding to a per-CC number of control channel candidatesthat are configurable for each CC of the set of CCs, and determine anapplied set of control channel candidates by allocating control channelcandidates across a number of configured control channel candidates ofthe set of CCs based on the CA limit and the per-CC limit, where thenumber of configured control channel candidates for at least one of theCCs may exceed the per-CC limit. The communications manager 1210 mayalso establish a wireless connection via two or more component carriers(CCs) using carrier aggregation (CA), communicate based on the appliedset of control channel candidates, identify a first subset of the two ormore CCs in which configured control channel candidates may exceed aper-CC limit of control channel candidates for each CC, the controlchannel candidates corresponding to locations for control channelprocessing objects for blind decoding (BD) or control channel elements(CCEs) for channel estimation, identify a second subset of the two ormore CCs in which the number of configured control channel candidatescomply with the per-CC limit of control channel candidates for each CC,and determine an applied set of control channel candidates for the firstsubset of CCs by mapping control channel candidates across the firstsubset of CCs such that mapped control channel candidates comply withthe per-CC limit.

Network communications manager 1215 may manage communications with thecore network (e.g., via one or more wired backhaul links). For example,the network communications manager 1215 may manage the transfer of datacommunications for client devices, such as one or more UEs 115.

Transceiver 1220 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1220 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1220 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1225.However, in some cases the device may have more than one antenna 1225,which may be capable of concurrently transmitting or receiving multiplewireless transmissions.

The memory 1230 may include RAM, ROM, or a combination thereof. Thememory 1230 may store computer-readable code 1235 including instructionsthat, when executed by a processor (e.g., the processor 1240) cause thedevice to perform various functions described herein. In some cases, thememory 1230 may contain, among other things, a BIOS which may controlbasic hardware or software operation such as the interaction withperipheral components or devices.

The processor 1240 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 1240 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into the processor 1240. The processor 1240 may beconfigured to execute computer-readable instructions stored in a memory(e.g., the memory 1230) to cause the device 1205 to perform variousfunctions (e.g., functions or tasks supporting search space design withoverbooking in carrier aggregation).

Inter-station communications manager 1245 may manage communications withother base station 105, and may include a controller or scheduler forcontrolling communications with UEs 115 in cooperation with other basestations 105. For example, the inter-station communications manager 1245may coordinate scheduling for transmissions to UEs 115 for variousinterference mitigation techniques such as beamforming or jointtransmission. In some examples, inter-station communications manager1245 may provide an X2 interface within an LTE/LTE-A wirelesscommunication network technology to provide communication between basestations 105.

The code 1235 may include instructions to implement aspects of thepresent disclosure, including instructions to support wirelesscommunications. The code 1235 may be stored in a non-transitorycomputer-readable medium such as system memory or other type of memory.In some cases, the code 1235 may not be directly executable by theprocessor 1240 but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

FIG. 13 shows a flowchart illustrating a method 1300 that supportssearch space design with overbooking in carrier aggregation inaccordance with aspects of the present disclosure. The operations ofmethod 1300 may be implemented by a UE 115 or base station 105 or itscomponents as described herein. For example, the operations of method1300 may be performed by a communications manager as described withreference to FIGS. 8 through 12. In some examples, a UE or base stationmay execute a set of instructions to control the functional elements ofthe UE or base station to perform the functions described below.Additionally or alternatively, a UE or base station may perform aspectsof the functions described below using special-purpose hardware.

At 1305, the UE or base station may establish a wireless connection viaa set of CCs using CA. The operations of 1305 may be performed accordingto the methods described herein. In some examples, aspects of theoperations of 1305 may be performed by a CA manager as described withreference to FIGS. 8 through 12.

At 1310, the UE or base station may determine a CA limit correspondingto a total number of configurable control channel candidates across theset of CCs, the control channel candidates including BD candidates orCCE candidates for channel estimation. The operations of 1310 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1310 may be performed by a CA limitcomponent as described with reference to FIGS. 8 through 12.

At 1315, the UE or base station may determine a per-CC limitcorresponding to a per-CC number of control channel candidates that areconfigurable for each CC of the set of CCs. The operations of 1315 maybe performed according to the methods described herein. In someexamples, aspects of the operations of 1315 may be performed by a CClimit component as described with reference to FIGS. 8 through 12.

At 1320, the UE or base station may determine an applied set of controlchannel candidates by allocating control channel candidates across anumber of configured control channel candidates of the set of CCs basedon the CA limit and the per-CC limit, where the number of configuredcontrol channel candidates for at least one CC of the set of CCs mayexceed the per-CC limit. The operations of 1320 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1320 may be performed by a control channel candidatecomponent as described with reference to FIGS. 8 through 12.

At 1325, the UE or base station may communicate based on the applied setof control channel candidates. The operations of 1325 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1325 may be performed by a CA manager as describedwith reference to FIGS. 8 through 12.

FIG. 14 shows a flowchart illustrating a method 1400 that supportssearch space design with overbooking in carrier aggregation inaccordance with aspects of the present disclosure. The operations ofmethod 1400 may be implemented by a UE 115 or base station 105 or itscomponents as described herein. For example, the operations of method1400 may be performed by a communications manager as described withreference to FIGS. 8 through 12. In some examples, a UE or base stationmay execute a set of instructions to control the functional elements ofthe UE or base station to perform the functions described below.Additionally or alternatively, a UE or base station may perform aspectsof the functions described below using special-purpose hardware.

At 1405, the UE or base station may establish a wireless connection viatwo or more CCs using CA. The operations of 1405 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1405 may be performed by a CA manager as describedwith reference to FIGS. 8 through 12.

At 1410, the UE or base station may identify a first subset of the twoor more CCs in which configured control channel candidates may exceed aper-CC limit of control channel candidates for each CC, the controlchannel candidates corresponding to locations for control channelprocessing objects for BD or CCEs for channel estimation. The operationsof 1410 may be performed according to the methods described herein. Insome examples, aspects of the operations of 1410 may be performed by aCC selection component as described with reference to FIGS. 8 through12.

At 1415, the UE or base station may identify a second subset of the twoor more CCs in which the number of configured control channel candidatescomply with the per-CC limit of control channel candidates for each CC.The operations of 1415 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1415may be performed by a CC selection component as described with referenceto FIGS. 8 through 12.

At 1420, the UE or base station may determine an applied set of controlchannel candidates for the first subset of CCs by mapping controlchannel candidates across the first subset of CCs such that mappedcontrol channel candidates comply with the per-CC limit. The operationsof 1420 may be performed according to the methods described herein. Insome examples, aspects of the operations of 1420 may be performed by acontrol channel candidate component as described with reference to FIGS.8 through 12.

At 1425, the UE or base station may communicate based on the applied setof control channel candidates. The operations of 1425 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1425 may be performed by a CA manager as describedwith reference to FIGS. 8 through 12.

It should be noted that the methods described above describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wirelesscommunications systems such as code division multiple access (CDMA),time division multiple access (TDMA), frequency division multiple access(FDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and other systems.A CDMA system may implement a radio technology such as CDMA2000,Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000,IS-95, and IS-856 standards. IS-2000 Releases may be commonly referredto as CDMA2000 1×, 1×, etc. IS-856 (TIA-856) is commonly referred to asCDMA2000 1×EV-DO, High Rate Packet Data (HRPD), etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. A TDMA system mayimplement a radio technology such as Global System for MobileCommunications (GSM).

An OFDMA system may implement a radio technology such as Ultra MobileBroadband (UMB), Evolved UTRA (E-UTRA), Institute of Electrical andElectronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal MobileTelecommunications System (UMTS). LTE, LTE-A, and LTE-A Pro are releasesof UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR,and GSM are described in documents from the organization named “3rdGeneration Partnership Project” (3GPP). CDMA2000 and UMB are describedin documents from an organization named “3rd Generation PartnershipProject 2” (3GPP2). The techniques described herein may be used for thesystems and radio technologies mentioned above as well as other systemsand radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NRsystem may be described for purposes of example, and LTE, LTE-A, LTE-APro, or NR terminology may be used in much of the description, thetechniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro,or NR applications.

A macro cell generally covers a relatively large geographic area (e.g.,several kilometers in radius) and may allow unrestricted access by UEs115 with service subscriptions with the network provider. A small cellmay be associated with a lower-powered base station 105, as comparedwith a macro cell, and a small cell may operate in the same or different(e.g., licensed, unlicensed, etc.) frequency bands as macro cells. Smallcells may include pico cells, femto cells, and micro cells according tovarious examples. A pico cell, for example, may cover a small geographicarea and may allow unrestricted access by UEs 115 with servicesubscriptions with the network provider. A femto cell may also cover asmall geographic area (e.g., a home) and may provide restricted accessby UEs 115 having an association with the femto cell (e.g., UEs 115 in aclosed subscriber group (CSG), UEs 115 for users in the home, and thelike). An eNB for a macro cell may be referred to as a macro eNB. An eNBfor a small cell may be referred to as a small cell eNB, a pico eNB, afemto eNB, or a home eNB. An eNB may support one or multiple (e.g., two,three, four, and the like) cells, and may also support communicationsusing one or multiple component carriers.

The wireless communications system 100 or systems described herein maysupport synchronous or asynchronous operation. For synchronousoperation, the base stations 105 may have similar frame timing, andtransmissions from different base stations 105 may be approximatelyaligned in time. For asynchronous operation, the base stations 105 mayhave different frame timing, and transmissions from different basestations 105 may not be aligned in time. The techniques described hereinmay be used for either synchronous or asynchronous operations.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the above description may berepresented by voltages, currents, electromagnetic waves, magneticfields or particles, optical fields or particles, or any combinationthereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a digital signal processor (DSP), anapplication-specific integrated circuit (ASIC), a field-programmablegate array (FPGA) or other programmable logic device (PLD), discretegate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices (e.g., a combinationof a DSP and a microprocessor, multiple microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suchconfiguration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described above can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media mayinclude random-access memory (RAM), read-only memory (ROM), electricallyerasable programmable read only memory (EEPROM), flash memory, compactdisk (CD) ROM or other optical disk storage, magnetic disk storage orother magnetic storage devices, or any other non-transitory medium thatcan be used to carry or store desired program code means in the form ofinstructions or data structures and that can be accessed by ageneral-purpose or special-purpose computer, or a general-purpose orspecial-purpose processor. Also, any connection is properly termed acomputer-readable medium. For example, if the software is transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, digital subscriber line (DSL), orwireless technologies such as infrared, radio, and microwave, then thecoaxial cable, fiber optic cable, twisted pair, DSL, or wirelesstechnologies such as infrared, radio, and microwave are included in thedefinition of medium. Disk and disc, as used herein, include CD, laserdisc, optical disc, digital versatile disc (DVD), floppy disk andBlu-ray disc where disks usually reproduce data magnetically, whilediscs reproduce data optically with lasers. Combinations of the aboveare also included within the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items(e.g., a list of items prefaced by a phrase such as “at least one of” or“one or more of”) indicates an inclusive list such that, for example, alist of at least one of A, B, or C means A or B or C or AB or AC or BCor ABC (i.e., A and B and C). Also, as used herein, the phrase “basedon” shall not be construed as a reference to a closed set of conditions.For example, an exemplary step that is described as “based on conditionA” may be based on both a condition A and a condition B withoutdeparting from the scope of the present disclosure. In other words, asused herein, the phrase “based on” shall be construed in the same manneras the phrase “based at least in part on.”

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label, or othersubsequent reference label.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, well-known structures and devices are shownin block diagram form in order to avoid obscuring the concepts of thedescribed examples.

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other variations withoutdeparting from the scope of the disclosure. Thus, the disclosure is notlimited to the examples and designs described herein, but is to beaccorded the broadest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. A method for wireless communication, comprising:establishing a wireless connection via a set of component carriers (CCs)using carrier aggregation (CA); determining a CA limit corresponding toa total number of configurable control channel candidates across the setof CCs, the control channel candidates including blind decoding (BD)candidates or control channel element (CCE) candidates for channelestimation; determining a per-CC limit corresponding to a per-CC numberof control channel candidates that are configurable for each CC of theset of CCs; determining an applied set of control channel candidates byallocating control channel candidates across a number of configuredcontrol channel candidates of the set of CCs based at least in part onthe CA limit and the per-CC limit, wherein the number of configuredcontrol channel candidates for at least one CC of the set of CCs mayexceed the per-CC limit; and communicating based at least in part on theapplied set of control channel candidates.
 2. The method of claim 1,wherein the determining the applied set of control channel candidatescomprises: allocating control channel candidates separately for each CCof the set of CCs, the control channel candidates for each CC allocatedto comply with the per-CC limit.
 3. The method of claim 1, wherein auser equipment (UE) is capable of supporting a first number of CCs, andwherein a second number of CCs in the set of CCs is less than or equalto the first number of CCs, and wherein the control channel candidatesfor each CC are separately allocated to each comply with the per-CClimit.
 4. The method of claim 1, wherein a user equipment (UE) iscapable of supporting a first number of CCs, and wherein a second numberof CCs in the set of CCs is greater than the first number of CCs.
 5. Themethod of claim 4, wherein the determining the applied set of controlchannel candidates comprises: selecting a subset of CCs from the set ofCCs, the subset of CCs having a third number of CCs corresponding to thefirst number of CCs; and allocating control channel candidates acrossthe subset of CCs, wherein the control channel candidates for each CC ofthe subset of CCs are separately allocated to each comply with theper-CC limit.
 6. The method of claim 4, wherein the per-CC limit foreach CC of the set of CCs is defined by a set of non-negative numberssuch that the per-CC limit is a product of a selected non-negativenumber, the first number of CCs, and a single carrier limit of controlchannel candidates that are configurable for a single non-CA carrier,and wherein the selected non-negative number is based at least in parton whether a BD limit budget or a CCE limit budget is distributedevenly, proportional to a bandwidth, or proportional to configuredcontrol channel candidates, for each CC.
 7. The method of claim 4,wherein the determining the applied set of control channel candidatescomprises: distributing a BD limit budget or a CCE limit budget evenlyacross the second number of CCs, wherein a portion of the BD limitbudget or the CCE limit budget for each CC corresponds to a product ofthe first number of CCs and the per-CC limit divided by the secondnumber of CCs.
 8. The method of claim 4, wherein the determining theapplied set of control channel candidates comprises: distributing a BDlimit budget or a CCE limit budget across the second number of CCsaccording to a bandwidth-proportional distribution, wherein a portion ofthe BD limit budget or the CCE limit budget for each CC corresponds to aproduct of the first number of CCs, the per-CC limit, and a bandwidth ofan associated CC, divided by a total cumulative bandwidth of the secondnumber of CCs.
 9. The method of claim 4, wherein the determining theapplied set of control channel candidates comprises: distributing a BDlimit budget or a CCE limit budget across the second number of CCsaccording to a slot-based proportional distribution, wherein a portionof the BD limit budget or the CCE limit budget for each CC correspondsto a product of the first number of CCs, the per-CC limit, and a numberof BDs or CCEs associated with the configured control channel candidatesof an associated CC for an associated slot, divided by a totalcumulative number of configured control channel candidates of the secondnumber of CCs.
 10. The method of claim 4, wherein the determining theapplied set of control channel candidates comprises: reducing a numberof CCs of the set of CCs that can be scheduled with control channeltransmissions to correspond to the second number of CCs, anddistributing a BD limit budget or a CCE limit budget across configuredcontrol channel candidates of the reduced number of CCs; or; andmaintaining the per-CC limit for a first subset of CCs and distributingremaining of the CA limit control channel candidates among remaining CCsof the set of CCs.
 11. The method of claim 1, wherein the determiningthe applied set of control channel candidates comprises: identifying aplurality of search space (SS) sets that indicate, for each CC of theset of CCs, associated resources for available control channelcandidates; and mapping the plurality of SS sets of each CC of the setof CCs up to the per-CC limit to determine the applied set of controlchannel candidates for a corresponding CC, wherein each CC of the set ofCCs has an ordered CC index, and wherein the mapping is from a lowest CCindex to a highest CC index.
 12. The method of claim 1, wherein thedetermining the applied set of control channel candidates comprises:identifying a plurality of search space (SS) sets that each indicateassociated resources for available control channel candidates for two ormore CCs, wherein each CC set has a SS set index; and mapping the eachCC associated with each SS set from the plurality of SS sets todetermine the applied set of control channel candidates for acorresponding SS set, wherein a control channel candidate for a CC isskipped if the per-CC limit for the corresponding CC is reached or theCC is fully mapped, and wherein the mapping is from a lowest SS index toa highest SS index.
 13. The method of claim 1, wherein a user equipment(UE) is capable of supporting a first number of CCs, and wherein asecond number of CCs in the set of CCs is greater than the first numberof CCs, and wherein the determining the applied set of control channelcandidates comprises: allocating control channel candidates jointly forthe set of CCs, the control channel candidates for each CC allocated tocomply with the per-CC limit and the CA limit.
 14. The method of claim13, wherein the allocating the control channel candidates comprises:identifying a plurality of search space (SS) sets that indicate, foreach CC of the set of CCs, associated resources for available controlchannel candidates; mapping the plurality of SS sets of each CC of theset of CCs up to the per-CC limit to determine the applied set ofcontrol channel candidates for the corresponding CC, wherein each CC ofthe set of CCs has an ordered CC index, and wherein the mapping is froma lowest CC index to a highest CC index; maintaining a cumulative countof mapped control channel candidates across the set of CCs; and stoppingthe mapping if the cumulative count reaches the CA limit.
 15. The methodof claim 13, wherein the allocating the control channel candidatescomprises: identifying plurality of search space (SS) sets that eachindicate associated resources for available control channel candidatesfor two or more CCs, wherein each CC set has a SS set index; mapping theeach CC associated with each SS set to determine the applied set ofcontrol channel candidates for the corresponding SS set, wherein acontrol channel candidate for a CC is skipped if the per-CC limit forthe corresponding CC is reached or the CC is fully mapped, and whereinthe mapping is from a lowest SS index to a highest SS index; maintaininga cumulative count of mapped control channel candidates across theplurality of SS sets; and stopping the mapping if the cumulative countreaches the CA limit.
 16. The method of claim 1, wherein the set of CCsincludes at least a first CC having a first sub-carrier spacing (SCS)and a second CC having a second SCS that is different than the firstSCS.
 17. The method of claim 16, wherein the first CC is a scheduling CCthat provides scheduling information for each of the CCs of the set ofCCs, and wherein the first SCS is used in determining the CA limit forthe scheduling CC and each of the CCs of the set of CCs that is providedscheduling information.
 18. The method of claim 16, wherein the first CCis a scheduling CC that provides scheduling information for the secondCC, and wherein the first SCS is used for the second CC for determiningthe applied set of control channel candidates.
 19. The method of claim16, wherein the determining the applied set of control channelcandidates comprises: allocating a BD limit budget or a CCE limit budgetseparately for each CC of the set of CCs based on control channelcandidates for each CC that are allocated to comply with the per-CClimit.
 20. The method of claim 16, wherein a user equipment (UE) iscapable of supporting a first number of CCs, and wherein a second numberof CCs in the set of CCs is greater than the first number of CCs, andwherein the determining the applied set of control channel candidatescomprises: identifying the first SCS as a reference SCS and identifyinga reference slot duration based on the reference SCS; determining asecond slot duration of the second CC based on the second SCS;determining the per-CC limit of the second CC based on the second slotduration relative to the reference slot duration; and allocating controlchannel candidates jointly for the set of CCs, the control channelcandidates for each CC allocated to comply with the per-CC limit and theCA limit.
 21. The method of claim 20, wherein the allocating the controlchannel candidates comprises: counting a number of control channelcandidates for each reference slot duration for each CC; calculating atotal number of control channel candidates for each CC in the referenceslot duration; and allocating a plurality of BDs or CCEs to a totalnumber control channel candidates for each CC to comply with the per-CClimit and the CA limit.
 22. The method of claim 21, wherein theallocating the control channel candidates further comprises: identifyinga plurality of search space (SS) sets that indicate, for each CC of theset of CCs, associated resources for available control channelcandidates; mapping the plurality of SS sets of each CC of the set ofCCs up to the per-CC limit to determine the applied set of controlchannel candidates for the corresponding CC, wherein each CC of the setof CCs has an ordered CC index, and wherein the mapping is from a lowestCC index to a highest CC index; maintaining a cumulative count of mappedcontrol channel candidates across the set of CCs; and stopping themapping if the cumulative count reaches the CA limit.
 23. The method ofclaim 21, wherein the allocating the control channel candidates furthercomprises: identifying plurality of search space (SS) sets that eachindicate associated resources for available control channel candidatesfor two or more CCs, wherein each CC set has a SS set index; mapping theeach CC associated with each SS set to determine the applied set ofcontrol channel candidates for the corresponding SS set, wherein acontrol channel candidate for a CC is skipped if the per-CC limit forthe corresponding CC is reached or the CC is fully mapped, and whereinthe mapping is from a lowest SS index to a highest SS index; maintaininga cumulative count of mapped control channel candidates across theplurality of SS sets; and stopping the mapping if the cumulative countreaches the CA limit.
 24. The method of claim 20, wherein the first SCSis smaller than the second SCS, the second SCS is the reference SCS, andfirst slot duration of the first CC is longer than the reference slotduration, and wherein the total number of control channel candidates foreach CC in the reference slot duration is adjusted based a portion ofthe first slot duration that overlaps with a subsequent reference slotduration.
 25. A method for wireless communication, comprising:establishing a wireless connection via two or more component carriers(CCs) using carrier aggregation (CA); identifying a first subset of thetwo or more CCs in which configured control channel candidates mayexceed a per-CC limit of control channel candidates for each CC, thecontrol channel candidates corresponding to locations for controlchannel processing objects for blind decoding (BD) or control channelelements (CCEs) for channel estimation; identifying a second subset ofthe two or more CCs in which the number of configured control channelcandidates comply with the per-CC limit of control channel candidatesfor each CC; determining an applied set of control channel candidatesfor the first subset of two or more CCs by mapping control channelcandidates across the first subset of two or more CCs such that mappedcontrol channel candidates comply with the per-CC limit; andcommunicating based at least in part on the applied set of controlchannel candidates.
 26. The method of claim 25, wherein the number ofconfigured control channel candidates complies with a per-CA limit ofcontrol channel candidates for the two or more CCs.
 27. The method ofclaim 25, wherein the first subset of the two or more CCs includes aprimary component carrier (PCC), a primary secondary component carrier(PSCC) and the second subset of the two or more CCs includes one or moresecondary component carriers (SCCs).
 28. The method of claim 25, whereinthe two or more CCs includes at least a first CC having a firstsub-carrier spacing (SCS), and a primary secondary component carrier(PSCC) and a second CC having a second SCS that is different than thefirst SCS.
 29. An apparatus for wireless communication, comprising: aprocessor, memory in electronic communication with the processor; andinstructions stored in the memory and executable by the processor tocause the apparatus to: establish a wireless connection via a set ofcomponent carriers (CCs) using carrier aggregation (CA); determine a CAlimit corresponding to a total number of configurable control channelcandidates across the set of CCs, the control channel candidatesincluding blind decoding (BD) candidates or control channel element(CCE) candidates for channel estimation; determine a per-CC limitcorresponding to a per-CC number of control channel candidates that areconfigurable for each CC of the set of CCs; determine an applied set ofcontrol channel candidates by allocating control channel candidatesacross a number of configured control channel candidates of the set ofCCs based at least in part on the CA limit and the per-CC limit, whereinthe number of configured control channel candidates for at least one CCof the set of CCs may exceed the per-CC limit; and communicate based atleast in part on the applied set of control channel candidates.
 30. Anapparatus for wireless communication, comprising: a processor, memory inelectronic communication with the processor; and instructions stored inthe memory and executable by the processor to cause the apparatus to:establish a wireless connection via two or more component carriers (CCs)using carrier aggregation (CA); identify a first subset of the two ormore CCs in which configured control channel candidates may exceed aper-CC limit of control channel candidates for each CC, the controlchannel candidates corresponding to locations for control channelprocessing objects for blind decoding (BD) or control channel elements(CCEs) for channel estimation; identify a second subset of the two ormore CCs in which the number of configured control channel candidatescomply with the per-CC limit of control channel candidates for each CC;determine an applied set of control channel candidates for the firstsubset of two or more CCs by mapping control channel candidates acrossthe first subset of two or more CCs such that mapped control channelcandidates comply with the per-CC limit; and communicate based at leastin part on the applied set of control channel candidates.